Building Info

  • Address:
    624 E. Mason St.
  • Taxkey:
  • Architect:
    Collings Engineers Inc.
  • Status:
  • Assessment:
    $1,987,000 (2014)
  • Year Built:
  • Size:
    41,705 sq-ft

The 660 Building is a five-story office building in downtown Milwaukee.

The building originally opened in 1963 with a plaza on the corner, but was later expanded to have a five-story corner office tower. It was built and originally home to Collings Engineers, Inc. Bauer Construction Company served as general contractor on the $1,300,000 project.

Cook & Franke SC, which dissolved in 2012, owned the building for a number of years and operated their law firm out of the building since at least 1988 until 2012.

When originally completed, the building was 27,000 square-feet. After the expansion, it reached 41,705 square-feet in size.

The building today is owned by a holding company of Northwestern Mutual, whose corporate headquarters are located across the street.

Learn More


ROW Occupancy Permit.
ROW Excavation Utility.

Building data on this page, including assessment information, was last updated on January 1, 1970

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