21 Astor is a residential and retail development located at 921 Northwest 21st Avenue, Multnomah County, Portland, Oregon 97210. Just over a quarter city block, 21 Astor features 27 residential units with 4,533 square feet of ground floor commercial and retail space. The apartment project is four stories and overall gross square feet of 42,869. Mr. Ball had the intention of making this smaller scale building high quality with a boutique type presence to it mirroring the neighborhood.