Abundance Ecovillage is a housing development outside Fairfield, Iowa. When I first visited Fairfield in 2004, there was only one house completed at the ecovillage, and another under construction. Since then it has grown into a community of dozens of houses; some are strawbale, some cob or other green building materials, and others are made of conventional materials but built to be super-efficient. In 2010 when I got my permaculture design certification, part of the ecovillage's land had been transferred to the Sustainable Living Coalition (SLC) and part to private ownership.
See an album of photos of the ecovillage and the adjoining SLC campus.