Wittnau is a municipality in the district of Laufenburg in the canton of Aargau in Switzerland.

Of the rest of the land, 0.75 km2 (0.29 sq mi) or 6.7% is settled (buildings or roads), 0.03 km2 (7.4 acres) or 0.3% is either rivers or lakes.

[3] The blazon of the municipal coat of arms is Azure two Eagles in pale displayed Argent langued beaked and membered Gules.

[7] The age distribution, as of 2008[update], in Wittnau is; 99 children or 8.8% of the population are between 0 and 9 years old and 191 teenagers or 17.0% are between 10 and 19.

[9] The historical population is given in the following table:[8] The Alt Homberg Castle ruin and the Wittnauer Horn (site of a prehistoric hill settlement, a Roman era settlement and an Early Middle Ages fortification) are listed as Swiss heritage sites of national significance.

[11] The entire village of Wittnau is designated as part of the Inventory of Swiss Heritage Sites.

[7] From the 2000 census[update], 715 or 63.2% were Roman Catholic, while 205 or 18.1% belonged to the Swiss Reformed Church.