16 River St. Apartments LLC has bought an eight-unit apartment building in Boston for $4.5 million.

The building is located in Boston’s Beacon Hill neighborhood at 16 River St. The seller was 16 River St. LLC, which was represented by Boston Realty Advisors. Marcus & Millichap represented the buyer.

"It was a special opportunity to work on this assignment, as the building’s one-of-a-kind location on the ‘flat of the hill’ was irreplaceable," BRA’s managing director and partner Christopher Sower says in a statement.