Somerville and New Brunswick recently saw the sale of three long-held apartment buildings for a combined $17.5 million, reflecting the region’s hot real estate market. In April, the Lexington and Jefferson Apartments in Somerville, owned by the same family for over 60 years, changed hands for $11.9 million. The Lexington features 54 units and Jefferson offers 64 garden-style apartments, both constructed in the early 1960s. The buyer, Lexington Residences 2, is linked to Pentaurus Properties with a varied real estate portfolio in New Jersey and Florida. In May, the family sold Century Apartments in New Brunswick—a 38-unit building from 1969—for $5.62 million to Century Apartments LLC, connected to Penn Properties Management. Berkadia’s Morristown office represented the sellers in both deals. The sales underscore strong demand and rising values in the local housing market, where prices for homes and apartments have increased significantly over the past year.