Delaware's Historic Preservation Office

The Delaware Historic Preservation Office (DHPO) is a state agency responsible for identifying, protecting, and promoting Delaware's historic resources under the administrative umbrella of the Delaware Division of Historical and Cultural Affairs, which is a component of the Delaware Department of State. The office administers Delaware's participation in the federal historic preservation program established by the National Historic Preservation Act of 1966, coordinating nominations to the National Register of Historic Places, reviewing federally funded projects for their effects on historic properties, and distributing federal preservation grants to property owners, local governments, and nonprofit organizations. Its work spans the full geographic range of Delaware, from the colonial streetscapes of New Castle and the industrial corridors of Wilmington to the agricultural landscapes of the Delmarva Peninsula and the maritime communities along Delaware Bay.

Statutory authority for the office derives from Delaware Code Title 7, Chapter 53, which governs historic preservation in the state. Through grants, tax incentives, regulatory review, and public education programs, the DHPO works with local governments, private property owners, nonprofit organizations, and federal agencies to preserve the architectural, archaeological, and cultural resources that document Delaware's history.

History

Delaware's formal commitment to historic preservation developed alongside the broader national movement that emerged after World War II, as rapid suburbanization and urban renewal projects threatened historic buildings and landscapes across the country. The state's early preservation efforts were largely ad hoc, driven by civic organizations and historical societies rather than a coordinated government program. That changed in 1966. The passage of the National Historic Preservation Act that year created the framework for a nationwide network of State Historic Preservation Offices (SHPOs), and Delaware moved to establish its own office in compliance with the federal mandate. The act required each participating state to survey historic properties, maintain a statewide inventory, nominate eligible properties to the National Register, and review the effects of federally assisted projects on historic resources. It's worth noting that earlier dates sometimes cited for the DHPO's founding, including references to a 1957 enabling act, have not been confirmed by the agency's own documentation and should be treated with caution until primary sources verify them.

The National Historic Preservation Act also established the Section 106 review process, which requires federal agencies to consult with SHPOs before approving projects that might affect properties listed on or eligible for the National Register. This function became one of the DHPO's most consequential roles. Thousands of federal undertakings, from highway construction to telecommunications projects, require DHPO review annually, giving the office significant influence over land use and development decisions throughout Delaware.

In the decades following the office's establishment, its scope expanded considerably. The 1970s and 1980s brought growing recognition that historic preservation needed to account for underrepresented communities whose heritage had been largely absent from earlier designation efforts. The DHPO began actively working to identify and document African American historic sites in Wilmington and elsewhere in the state, as well as the landscapes associated with Indigenous peoples and immigrant communities. A parallel expansion occurred in the archaeological program, as the office developed standards for archaeological surveys required under Section 106 and for state-funded projects.

The office also played a central role in documenting Delaware's industrial heritage. Working with institutions like the Hagley Museum and Library, the DHPO helped preserve the legacy of the DuPont Company's early manufacturing operations along the Brandywine Creek, including powder mills and worker housing that represent some of the earliest large-scale industrial complexes in North America. Today the office continues to adapt its programs, addressing emerging challenges including the effects of climate change on historic properties and the need to integrate digital survey tools into its statewide inventory work.

Administration and Legal Authority

The DHPO operates within the Delaware Division of Historical and Cultural Affairs, which sits under the Delaware Department of State rather than the Department of Natural Resources and Environmental Control. This distinction matters practically: state historic sites and museums in Delaware are managed by the Division of Historical and Cultural Affairs, while natural resource lands are managed separately by DNREC. The DHPO serves as Delaware's State Historic Preservation Officer program, the point of contact between state government and the federal historic preservation system administered by the National Park Service.

Delaware Code Title 7, Chapter 53 gives the DHPO authority to designate historic properties under state law, regulate alterations to state-designated landmarks, and administer grant programs funded through the federal Historic Preservation Fund. The office also coordinates with the Advisory Council on Historic Preservation in Washington when Section 106 reviews involve particularly complex or controversial undertakings. Locally, the DHPO works alongside municipal historic district commissions in cities like Wilmington and Dover, providing technical guidance on design standards and preservation best practices.

National Register of Historic Places

Delaware has a substantial number of properties listed on the National Register of Historic Places, spanning individual buildings, historic districts, archaeological sites, and cultural landscapes. The DHPO manages the nomination process for Delaware properties, evaluating whether sites meet the National Register's criteria for significance in history, architecture, archaeology, engineering, or culture, and whether they retain sufficient physical integrity to convey that significance. Nominations are reviewed first by the Delaware State Review Board for Historic Preservation before being forwarded to the National Park Service for final listing.

Listed properties in Delaware range from the New Castle Historic District, which preserves one of the most intact colonial-era town centers on the East Coast, to 19th-century farmsteads in Sussex County, 18th-century churches, and the industrial complexes of the Brandywine Valley. The Winterthur Museum, Garden and Library and the Hagley Museum and Library are both National Historic Landmarks, the highest designation within the National Register system, reflecting their exceptional national significance.

Listing on the National Register does not restrict what private property owners can do with their own property. It does, however, make them eligible for federal historic preservation tax credits, which provide a 20 percent income tax credit for the certified rehabilitation of income-producing historic buildings. The DHPO administers the certification process for these credits in Delaware, reviewing proposed rehabilitation plans to ensure they meet the Secretary of the Interior's Standards for Rehabilitation.

Section 106 Review

One of the DHPO's most active functions is administering the Section 106 review process under the National Historic Preservation Act. Section 106 requires federal agencies to consider the effects of their undertakings on historic properties before approving permits, issuing licenses, or disbursing federal funds. In practice, this means that virtually any project receiving federal money or requiring a federal permit, from road expansions and utility installations to telecommunications tower construction and federally funded housing rehabilitation, must be reviewed by the DHPO if historic properties might be affected.

The review process begins with identification: federal agencies, often working with project applicants, must identify historic properties in the project's area of potential effect. The DHPO then assesses whether the project will have an adverse effect on those properties. If it will, the agency, applicant, DHPO, and other consulting parties negotiate a Memorandum of Agreement outlining mitigation measures, which might include archaeological excavation before ground disturbance, facade preservation, or documentation of buildings that can't be saved. Not every review results in conflict. Many Section 106 consultations conclude quickly when projects are designed to avoid historic resources or when no significant properties are present.

The Section 106 process has shaped major infrastructure decisions in Delaware. Highway realignments, bridge replacements, and redevelopment projects in historic downtown areas have all been modified through Section 106 consultation to reduce impacts on listed properties and historic districts. This regulatory role gives the DHPO influence well beyond its grant-making activities.

Geography

Delaware's compact size belies significant geographic diversity, and the DHPO's preservation work reflects that variety. The northern part of the state, anchored by Wilmington and New Castle County, contains the highest concentration of urban historic resources: Federal-period row houses, Victorian commercial blocks, 20th-century industrial buildings, and the colonial streetscapes of New Castle itself. The Brandywine Valley, straddling the Pennsylvania border, contains a particularly rich concentration of 18th- and 19th-century country houses, mills, and designed landscapes, including the estates now occupied by Winterthur Museum, Garden and Library and other institutions.

Central Delaware, dominated by Kent County and the capital city of Dover, preserves a different character: a mid-Atlantic agricultural landscape punctuated by 18th-century courthouse towns, plantation-era farmsteads, and the historic core of Dover itself, where the Old State House and Legislative Hall anchor a district that has been central to Delaware governance since the colonial period. Southern Delaware, comprising Sussex County, contains the state's greatest concentration of rural historic resources, including 19th-century farmsteads, small crossroads towns, African American churches and schools from the post-Civil War era, and the maritime communities along the Delaware Bay and Atlantic Coast.

The DHPO uses geographic information systems (GIS) to maintain and analyze its statewide inventory of historic properties, allowing staff to identify survey gaps, plan targeted fieldwork, and provide data to local governments and federal agencies conducting Section 106 reviews. Coastal areas present particular challenges. Rising sea levels and increasing storm intensity threaten historic resources in communities like Lewes and along the Delaware Bay shoreline, and the DHPO has been working to integrate climate vulnerability assessments into its survey and planning work.

Climate Change and Historic Properties

Climate change poses a direct and growing threat to Delaware's historic resources, particularly in the coastal and low-lying areas that contain some of the state's most significant properties. Delaware is among the most vulnerable states on the East Coast to sea level rise, with projections from the National Oceanic and Atmospheric Administration indicating continued increases in tidal flooding frequency throughout the century. Historic structures built in the 18th and 19th centuries were not designed with these conditions in mind, and repeated flooding causes cumulative damage to foundations, masonry, and wood framing that standard maintenance programs can't easily address.

The accuracy of existing flood zone designations is a legitimate concern. Federal Emergency Management Agency flood maps, which designate 100-year and 500-year flood zones, are updated periodically but often lag behind observed changes in flooding patterns caused by climate change and local development. Property owners in areas formally designated as low-risk have in some cases experienced repeated flooding events, raising questions about whether current maps adequately reflect actual risk to structures in those areas. For historic properties, this gap between official designation and experienced reality is particularly consequential: flood insurance decisions, grant eligibility, and local ordinance requirements are all tied to FEMA flood zone status.

The DHPO has begun incorporating climate resilience considerations into its technical guidance for historic property owners and into its survey prioritization. Preserving a building's historic character while improving its resilience to flooding is a challenge, since flood mitigation measures like elevating structures, installing flood barriers, or waterproofing masonry can conflict with the Secretary of the Interior's Standards for Rehabilitation that govern federally assisted preservation work. The office works with property owners and the National Park Service to identify approaches that protect historic integrity while reducing vulnerability. Still, the pace of adaptation in government programs has generally been reactive, responding to damage after major storms rather than systematically addressing risk before it materializes.

African American Heritage

Delaware's African American heritage represents one of the DHPO's most important and historically underserved areas of preservation work. The state's history encompasses the full arc of the African American experience from enslavement through emancipation, the Great Migration, and the Civil Rights Movement, and significant physical resources associated with that history survive across all three counties.

In Wilmington, the DHPO has worked to identify and document historic African American neighborhoods, churches, and institutions, including resources associated with the city's role as a destination for African American migrants from the South during the early 20th century. Wilmington's African American community sustained a network of churches, fraternal organizations, and businesses that are documented in the statewide historic property inventory, though the level of formal National Register designation for these resources continues to lag behind their historical significance. That gap has been a focus of targeted survey work in recent years.

Rural Sussex County contains a particularly significant concentration of African American heritage resources, including the Colored School buildings constructed under the Julius Rosenwald Fund program in the early 20th century and the small rural churches that served as community anchors during the era of legal segregation. The DHPO has supported survey and nomination work focused on these resources, recognizing that their significance extends beyond Delaware to the broader national narrative of African American education and community institution-building.

Economy

Historic preservation generates measurable economic activity in Delaware, both through direct tourism spending and through the private investment stimulated by preservation tax incentives. The federal Historic Tax Credit program, administered in part through the DHPO's certification process, has financed the rehabilitation of historic commercial and industrial buildings in Wilmington and other Delaware cities, converting underused structures into housing, office space, and retail uses that contribute to local tax bases. Studies of the federal tax credit program nationally have consistently found that rehabilitation of historic buildings generates more construction jobs per dollar invested than new construction, because rehabilitation is more labor-intensive and relies less on prefabricated materials.

Tourism tied to historic sites is a significant component of Delaware's visitor economy. The First State Heritage Park in Dover, a partnership among state agencies and nonprofit organizations that connects historic sites across the capital city, draws visitors to the Old State House, the historic Green, and other downtown landmarks. The Brandywine Valley's concentration of museums, gardens, and historic sites, including Winterthur and Hagley, attracts regional visitors who generate spending in hotels, restaurants, and retail. Cape Henlopen and the historic town of Lewes together form another visitor draw on the Atlantic Coast, combining natural heritage with a colonial-era townscape that the DHPO has helped protect through survey, designation, and technical assistance to local historic district boards.

Property values in designated historic districts in Delaware generally perform competitively with comparable non-designated areas, a pattern documented in studies of historic district economics nationally. The effect is most visible in neighborhoods like the New Castle Historic District and portions of downtown Dover, where designation has helped stabilize property values and attract reinvestment.

Attractions

The DHPO supports and promotes a range of historic sites and attractions across Delaware, though it's the Division of Historical and Cultural Affairs that directly manages many of the state-owned historic sites and museums. Among the most visited is the Hagley Museum and Library, a National Historic Landmark occupying the site of E.I. du Pont's original black powder mills along the Brandywine Creek. The museum's collection documents the history of American industry and technology, and its restored mill buildings, workers' community, and Georgian-style residence offer visitors a detailed picture of early American industrial enterprise.<ref>[https://www.hagley.org/about "About