This dataset provides a single county subset of Microsoft's computer-generated building footprints. The original footprints, covering all 50 US States, were created via a two-stage process. In the first step, semantic segmentation, a deep neural network was used to recognize building pixels on Bing aerial imagery, which is a composite of multiple sources of varying dates. In the second step, building pixels blobs were converted into polygons. It is not perfect, particularly in dense urban areas. For the 2021 v2 release, selected areas were updated with 2019-2020 imagery. This dataset provides a relatively complete dataset of building outlines, especially useful for areas where official building footprints may not exist.