Obermumpf is a municipality in the district of Rheinfelden in the canton of Aargau in Switzerland.

It is likely that there was a Hallstatt culture settlement near Obermumpf, though the exact site has not been discovered.

After the Act of Mediation in 1803, the entire Fricktal, including Obermumpf, went to the newly formed Canton of Aargau.

The low justice right was held by the manor house Stein, which was owned by Säckingen Abbey.

[3] Obermumpf has an area, as of 2009[update], of 5.03 square kilometers (1.94 sq mi).

Of the rest of the land, 0.46 km2 (0.18 sq mi) or 9.1% is settled (buildings or roads), 0.01 km2 (2.5 acres) or 0.2% is either rivers or lakes.

[4] The municipality is located in the Rheinfelden district, in the Fricktal (Frick river valley).

The blazon of the municipal coat of arms is Or a Key and a Sword in saltire both Azure handled Sable.

[8] The age distribution, as of 2008[update], in Obermumpf is; 95 children or 9.4% of the population are between 0 and 9 years old and 147 teenagers or 14.5% are between 10 and 19.

[10] About 61% of the total households were owner occupied, or in other words did not pay rent (though they may have a mortgage or a rent-to-own agreement).

[8] From the 2000 census[update], 551 or 56.2% were Roman Catholic, while 160 or 16.3% belonged to the Swiss Reformed Church.