WASHINGTON,DC-MARCH 22: Entrance and mirroring stairways in the Carnegie Library building at Mt Vernon Square in Washington DC, the present location of The Historical Society,on March 22, 2011 ( Photo by Jeffrey MacMillan/For Washington Post) (Jeffrey MacMillan/FOR WASHINGTON POST)

The District’s convention and sports authority, Events D.C., has signed a lease amendment with the Historical Society of Washington for the Carnegie Library at Mount Vernon Square.

Under the agreement, Events D.C. is to develop and operate special-event space in the building. The Historical Society is to continue to use the building for its headquarters, the Kiplinger Research Library and exhibit galleries for its collections of historical materials.

Events D.C. took control of the Carnegie Library, including the remaining 88 years on the Historical Society’s lease, from the District government in May.

The Historical Society is to turn over about 80 percent of the building to Events D.C., which will develop new uses for the space, including a visitors center with information on current events, maps and neighborhood-level information.

In return, Events D.C. is to operate and maintain the 110-year-old building, which is listed on the National Register of Historic Places, with the Historical Society as a tenant, allowing the nonprofit to focus on operations and programs, which will continue to be located at the library.

In Reston, one firm moves in, another decides to stay

RESTON — One law firm has decided to relocate here, while another one has decided to remain, but will take larger premises.

Law firm Odin, Feldman & Pittleman has signed a long-term lease for 53,918 square feet at 1775 Wiehle Ave.

The law firm plans to relocate their office from its current location at 9302 Lee Highway in Fairfax next fall.

The Marbury Law Group has signed a long-term lease for the 12,891-square-foot 15th floor at the JBG Cos.-owned Reston International Center.

The firm currently occupies 8,185 square feet on the 10th floor of the same building at 11800 Sunrise Valley Dr.

The Ezra Co., which negotiated the lease for Marbury, said the firm received an 18 percent rent reduction.

Marbury said it plans to move into its new space by the middle of December.

Architect Building sold for nearly $59M

ARLINGTON — Boston-based Great Point Investors has sold 1400 Wilson Blvd. to Charlotte, N.C.-based Salus Property Investments for $58.95 million or $544 per square foot, according to public records.

The 12-story, 108,296-square-foot, Class B office property is also known as the Architect Building, and is near the Rosslyn Metro Station, along the Wilson Boulevard corridor. The State Department holds a long-term lease in the building.

Lockton takes space at 1801 K St. NW

WASHINGTON — Lockton Cos., an insurance, risk management and employee benefit company, has leased 21,761 square feet in the office building at 1801 K St. NW.

The 13-story, 569,769-square-foot Class A property was constructed in 1969 in the central business district. Its renovation was completed in 2009.

River Pointe sold for $15.2M

FORT WASHINGTON — Federal Capital Partners has acquired the River Pointe apartments from the Bozzuto Group for $15.2 million or $89,412 per unit.

The 170-unit multifamily complex at 8318 Indian Head Highway contains six buildings and comprises 117,781 square feet. The Class B property was built in 1969.

Leasing agent named for Kincora Center

STERLING — Developers Norton Scott LLC and Tritec Real Estate Co. selected Colliers International as the primary leasing agent for its Kincora Center, a 400-acre mixed-use project in Loudon County.

Kincora Center is at the intersection of routes 7 and 28. The development has approximately 6.7 million square feet of leasable space. The project is a mix of retail, residential and office space.

The project also includes a performing arts center, ballpark and a 140-acre park that connects the W&OD Trail with the Potomac Heritage Trail.

Parkwood Court sold for $23M

ALEXANDRIA — Baltimore-based Continental Realty Acquisitions has bought the Parkwood Court apartment complex from CRS Alexandria Corp. for $23 million.

The 189-unit complex is located at 101 N. Ripley St. and is nearly 94 percent leased. Continental said it plans a major renovation.

— From CoStar Group and news releases