[1] While various Roman era bricks and coins have been discovered, the first record of Oberflachs is in 1342 as Obreflaht.

[2] From the Middle Ages until 1732, Kasteln Castle held the rights to low justice in the village.

The rights to administer High Justice was held by the bailiwick of Schenkenberg and was acquired in 1460 by the city of Bern.

The poverty and collapse of the wine industry forced many residents (particularly in the 1880s) to emigrate overseas.

A merger of Oberflachs with four municipalities failed in 2009 because Veltheim voters rejected the proposal.

Of the rest of the land, 0.3 square kilometers (0.12 sq mi) or 8.9% is settled (buildings or roads).

34.6% of the total land area is heavily forested and 3.0% is covered with orchards or small clusters of trees.

The blazon of the municipal coat of arms is Argent three Flax flowers Azure seeded Or slipped and leaved Vert in saltire and in pale.

[3] The age distribution, as of 2008[update], in Oberflachs is; 56 children or 11.7% of the population are between 0 and 9 years old and 70 teenagers or 14.6% are between 10 and 19.

[9] The historical population is given in the following table:[2] The village of Oberflachs is designated as part of the Inventory of Swiss Heritage Sites.

[3] From the 2000 census[update], 76 or 16.2% were Roman Catholic, while 340 or 72.6% belonged to the Swiss Reformed Church.