Residents who vehemently opposed plans to build National Harbor, the $2 billion development on the Potomac River in Prince George's County, dropped their lawsuit against the project's developer yesterday.

Donna Edwards, an attorney for the Campaign to Reinvest in Oxon Hill, said the decision was made after reaching an agreement this week with Milton Peterson, president of the Peterson Cos., who is National Harbor's developer.

A formal announcement of the accord is expected today.

In exchange for ending the five-year battle, Edwards said, Peterson has agreed to hire a consultant to develop a plan for downtown Oxon Hill; build a bicycle and walking trail along the Potomac; set aside a specific portion of the site for residential development; pay for a consultant to create a two-lane design for Oxon Hill Road; and work with the county and community leaders to bring a Metro rail station to downtown Oxon Hill.

"We all did not get what we wanted, but we all got something, and the community benefits as a result," Edwards said. "We could not have a development in our community that would serve the needs of tourists and others and not the serve the needs of the residents of this county."

Peterson, who has negotiated with residents for several months, was not available for comment yesterday.

The Campaign to Reinvest in the Heart of Oxon Hill has been a formidable opponent of National Harbor.

It tied up Peterson in court for several months last year, later winning a ruling that forced him to reduce the number of office units planned for the property. Campaign members have hung protest signs in their yards, including one posing the question, "What is National Harbor?"

"We've not only had our voice be heard, but we are now at the table," said Bonnie Bick, a vocal opponent of the project and a member of the Sierra Club. "This is not an ending; it's really a beginning."

Bick, who has fought National Harbor since the mid-1990s when Peterson bought the 500-acre parcel, said she was happy to conclude the contentious battle, which had at one point seen her house set for demolition to accommodate anticipated traffic generated by the resort.

Bick said her house is no longer in jeopardy.

Edwards said the decision to drop the litigation does not preclude the group from raising concerns about the possibility of gambling at National Harbor.

The resort has repeatedly been discussed as a potential site for slot machines if state lawmakers legalize gambling in Maryland.

"We have a provision in the agreement that this doesn't prohibit us from working against slot machines or casinos at National Harbor," Edwards said. "We've made a multimillion-dollar investment in National Harbor, and we can't have that undermined by slot machines or casinos in Prince George's County."

Edwards's decision to end the litigation clears another hurdle for Peterson in his quest to build a conference center, hotels and restaurants along the Potomac. Last month, the County Council designated the planned hotel and convention center as a special tax district and approved issuance of $160 million in bonds to pay for roads, sewer and other infrastructure for the site.