Millenium Partners, developer of the MIllenium Tower at 301 Mission St., on Thursday opened a sales office at 450 Mission St.

The 645-foot, 60-story tower—the tallest residential building west of the Mississippi– will include 419 residential units ranging from 750 to 6,000 square feet in size.

The tower will also include two retail tenants at ground level including rn74, a restaurant operated by chef Michael Mina.