UDR is a real estate investment trust primarily engaged in the acquisition, management, and development of multifamily apartment communities in urban submarkets throughout the United States. UDR divides its real estate portfolio into West, Mid-Atlantic, Southeast, Northeast, and Southwest geographic segments. Cumulatively, the vast majority of the company's real estate assets are located in the western, mid-Atlantic, and northeastern areas of the U.S. in terms of the total value. The urban markets of metropolitan Washington D.C.; New York City; Orange County, California; and San Francisco, specifically, account for the majority of the value of UDR's real estate property portfolio. The company derives nearly all of its revenue in the form of rental income from leases.