The Prince George’s County Planning Board on Thursday gave preliminary approval to plans that would bring a collection of high-end outlet stores just outside the Capital Beltway, ­despite numerous objections from residents who said the proposal would further clog roadways and create an eyesore near historic Oxon Hill Manor.

The unanimous decision followed six hours of testimony from more than three dozen people.

“We’re very pleased with the progress to date,” said Andre Gingles, a lawyer for The Peterson Cos. “The Peterson Companies and Tanger know that collectively they are going to build a great asset for the county.”

The Planning Board was also scheduled late Thursday to consider another proposal by the Cafritz family that would give the county its first Whole Foods Market, along Route 1 in Riverdale Park.

Many residents near the proposed Tanger Outlet site raised questions about the development’s proximity to Oxon Hill Manor, which is on the National Register of Historic Places, and the additional traffic congestion and stormwater management problems they said the project would create.

“The entire community has been held hostage by traffic,” said Mike Little, who lives in Oxon Hill. “It’s bad now. If we just bring stuff in and not take care of the residents of the community, we do a disservice.”

Little said he supported the concept of the project, recognizing the need for the creation of jobs and economic development, but he said the county “has to step up to its responsibility and fix Oxon Hill Road.”

Several people said that the property is too small to accommodate a 460,000-square-foot development and that a 20-foot buffer, as suggested by the developer, was not nearly sufficient. Residents who oppose the project said the buffer should be 100 feet.

Karen Herigstad, a resident of Fort Washington for 14 years, said her quality of life has worsened since the opening of ­National Harbor. She expects conditions to get even worse with Tanger.

“We have no view, and they are ready to do it again,” she said.

Taylor Chess, senior vice president of retail for Peterson, said Tanger would compliment ­National Harbor and give Gaylord National Resort and Convention Center a competitive advantage in the convention industry.

Several historic preservationists said Thursday that they supported the project after working for months with Peterson on its decision to build on the site of Salubria, a historic Oxon Hill plantation where a 14-year-old slave purportedly poisoned her master’s three children.

The hearing for the Cafritz property in Riverdale began with a resident asking the board to consider a continuance. The developer submitted significant changes to its application Thursday without allowing residents time to review the new application, he said.

Planning Board member Dorothy Bailey said the board would continue because more than 70 people had signed up to testify. By 9:30 p.m., fewer than 10 people had spoken.

Local elected officials have met with representatives of the developer during the past several months, trying to hammer out agreements over design, stormwater management and traffic mitigation.

One of the biggest sticking points is the construction of a bridge over the CSX tracks to the east of the property, which would allow better access to the project.

Riverdale Park, University Park and Hyattsville officials voted this week to support the rezoning with several conditions — including an agreement that phases in the construction of the development based on progress the developer makes on the bridge. For example, no permits would be issued for more than 100,000 square feet of retail, office and hotel space and no more than 120 residential units until construction of the CSX crossing is at least 50 percent completed, according to the county department of public works and transportation.

College Park officials decided Wednesday night to oppose the project.