Albert Hatt, a Napa merchant, was born in Prussia. His Hatt Building is the largest brick industrial building in Napa. It is actually four contiguous brick structures built over a period of forty years with bricks made from Napa River clay.

The original building was a two-storey feed and grain mill. An 1885 addition was used as a skating rink and for social and civic activities. Today the buidling houses a hotel, restaurants and retailers.

The Hatt Building has been in continuous use since its construction.