Salesforce Tower, formerly known as Transbay Tower, is a 61-story supertall skyscraper at 415 Mission Street, between First and Fremont Street, in the South of Market district of downtown San Francisco. Its main tenant is Salesforce, a cloud-based software company. The building is 1,070 feet (326 m) tall, with a top roof height of 970 feet (296 m). Designed by César Pelli and developed by Hines Interests Limited Partnership and Boston Properties, it was the last building designed by Pelli to be completed in his lifetime. As of 2024, Salesforce Tower is the tallest building in San Francisco and the second-tallest building both in California and west of the Mississippi River after the 1,100-foot (335 m) Wilshire Grand Center in Los Angeles.