Built for Industry on the Road to the Depot

A mill first went up on this site around 1853, when Detroit Street was one of the busiest corridors in town — the main route connecting the railroad depot to the county courthouse. That first mill burned, and in 1869 John G. Miller rebuilt the brick planing mill that still stands today, producing sash, doors, shutters, moulding, and scroll work for a fast-growing city. The Ann Arbor District Library’s local history archive notes that an engraving of the mill — and the miller’s house still standing next door at 521 Detroit — appeared in the 1874 Atlas of Washtenaw County.

As Detroit Street’s industrial era faded, the building kept adapting: by 1940 it housed the Warehouse Furniture Store, and in the 1950s it was home to Ann Arbor Fruit and Produce.

Sixty Years as the Treasure Mart

In 1960, Demaris Cash rented the old mill and opened the Treasure Mart, a consignment shop that became one of Ann Arbor’s most cherished institutions. Cash eventually bought the mill and the miller’s house in 1983, and for six decades three floors of antiques, china, art, and one-of-a-kind finds drew regulars and visitors alike — until the shop closed in August 2020, as chronicled in the library’s Treasure Mart retrospective.

What 525 Detroit Street Is Becoming

In 2021, Redeemer Ann Arbor, a local church that had already restored the historic Deke Shant downtown, purchased the property for just over $2 million, according to the Ann Arbor Observer. Because the building sits in the Old Fourth Ward Historic District, the renovation is a true preservation project: the Historic District Commission approved plans to restore the exterior to its late-1800s appearance, with a modest addition of roughly 1,300 square feet and reuse of the miller’s house at 521 Detroit.

The project has moved slowly — the church reapplied for its Special Exception Use approval in 2026 after the original approval expired due to delays, per the City of Ann Arbor’s planning updates — but work is well underway, and Redeemer hopes to occupy the building by late 2026.

• Why it matters for the neighborhood: rather than demolition or a new build, one of Kerrytown’s oldest industrial buildings is being restored to its 19th-century character.
• Future use: a community gathering space in a walkable historic district — a fitting next chapter for a building that has always served the public in one form or another.