The Howard County Council Monday night unanimously approved the extension of public water and sewer lines to a 221-acre site on historic Doughoregan Manor, the nearly three-century-old Ellicott City estate of Charles Carroll of Carrollton, a signer of the Declaration of Independence.

Carroll's descendants hope to build 325 homes on the land just south of Frederick Road, and donate 34 acres to the county for a park, while preserving the rest of the 892-acre estate. Obtaining council approval to move public utilities is a vital step in that plan, though the land must still be rezoned for it to work. The idea is to cluster the new homes and preserve the rest of the land.

The council amended the bill to add safeguards for residents in a negotiated agreement between the county and the Carroll family to ensure the complex parts of the deal are carried out.

Nearby residents worried about traffic congestion and wastewater treatment oppose the development, which is intended to give the family enough money to restore their 282-year-old mansion and several historic outbuildings, and keep the property in family hands for many more decades.