Anao covers a total land area of 23.87 square kilometres. The area occupied by the municipality was formerly a part of Pangasinan. According to the 2000 census, it has a population of 10,045 people in 2,086 households.
Aglipayan and Roman Catholicism are two of the predominant religions.
The area where Anao is located was inhabited before 1800 by people from the Ilocos Region. In 1835, a group of immigrants from Paoay, Ilocos Norte reached the region and first settled near a creek on the bank where there were balete trees. These immigrants called their settlement "Balete". The immigrants found that the region where they settled has many agricultural prospects and this attracted more immigrants who came from the north, especially from the town of Paoay. The settlement expanded and became a barrio named Balete which later changed to Barrio Anao deriving from the Ilocano word "Danao" which means creek. By that time, balete trees were extinguished and the barrio was adjacent in all directions by creeks. Paniqui then stood as one municipality and had a road extended toward the east to Barrio Anao. Paniqui had more rights to claim Anao as its barrio and the people of the barrio accepted the claim.
Anao is politically subdivided into 18 barangays.