Isolated finds of artifacts indicate settlement during the Neolithic, Roman and Alamanni eras.

The village was part of the lands of the Counts of Lenzburg, the Kyburgs and the finally the Habsburgs.

The power of Zwing und Bann (Manor rights as well as low justice) over the village, was held by the Lords of Hohenklingen through the von Birrwil family.

Following the Bernese conquest of the Aargau in 1415 became part of Bern until the end of the Old Swiss Confederacy in 1798.

[4] The former manor houses were only fully incorporated in the 19th and 20th century into Birrwil (Schwaderhof 1822, Wilhof 1905).

[4] Birrwil is located in the Seetal valley, on the western shore of Lake Hallwil.

It is situated on four thin terraces on the steep east slopes of Mounts Eichhalde and Güggeliberg, between 70 and 150 meters (230 and 490 ft) above the lake surface.

Neighboring municipalities are Leutwil in the north-west, Boniswil in the north, Meisterschwanden in the east, Beinwil am See in the south, Reinach in the south-west, and Zetzwil in the west.

Of the rest of the land, 0.45 square kilometers (0.17 sq mi) or 13.2% is settled (buildings or roads).

25.4% of the total land area is heavily forested and 3.2% is covered with orchards or small clusters of trees.

[5] The blazon of the municipal coat of arms is Azure a Pear Branch leaved Vert and fructed Argent and coupeaux of the second.

[11] About 61.3% 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).

[9] From the 2000 census[update], 217 or 22.6% were Roman Catholic, while 557 or 58.0% belonged to the Swiss Reformed Church.