Upper Marlboro contains nearly 100 acres of historic homes dating back to the mid-18th, 19th and 20th centuries. Thanks to the town’s architectural progression and notable housing styles, the National Park Service added Upper Marlboro to its list of historic districts in the National Register of Historic Places.

Town officials and residents say the Dec. 12 designation will help provide a sense of pride and preservation among those living within the historic district, which encompasses much of the town’s boundaries.

Officially, being named on the historic registry prevents state and federal projects such as major highways from being built over the district without conducting a number of additional requests and studies.

Steve Sonnett, chairman of the town’s board of commissioners, said a more than 45-page application detailing the town’s makeup was submitted to the National Park Service for review of Upper Marlboro’s historic qualities.

“The thrust of the designation is that it’s an old town and has old houses and has period houses. The houses have shown a progression of an old town through time,” said Sonnett, remarking on the variety of homes built over various centuries. “There was an effect on our part to say, ‘Look, you’re living in a neat little town here, and it should be recognized as such. Let’s work on preserving that and building upon that.’ ”

To be considered for the historic district designation, neighborhood houses and structures must be at least 50 years old, Sonnett said. There are more than 90 homes and structures listed in the application.

In 1695, settlers came to Upper Marlboro, which was established as a port town for tobacco shipments in 1706. The town has been the county’s headquarters since 1721.

The historic district boundary encompasses the residential neighborhoods but excludes the town’s downtown area, which houses the county’s district courthouse, administration building and various shops and businesses, and more than 100 newer townhouses on the north edge of town.

Brian Callicott, 45, a self-proclaimed “history enthusiast,” said he moved to Upper Marlboro for its historic homes and has visited many historic places around the region after finding them on the register.

“If it’s a historic district, it must have enough stuff there that I would want to check it out,” Callicott said. “Lots of history-minded folks jump online and say, ‘Where are these historic districts?’ ”

Upper Marlboro is one of 12 historic districts in Prince George’s County. The others are Greenbelt, Hyattsville, Mount Rainier, University Park, Calvert Hills, Riverdale Park, West Riverdale, North Brentwood, Old Town College Park, College Heights Estates and Brandywine.

Howard Burger, supervisor of the county’s historic preservation section, said the designation provides recognition of the significant aspects of such towns.

“We find it’s a great way for local communities to recognize their significance,” Burger said. “It really allows people to have an interest in their community and take pride in it.”