Siegelsum is an East Frisian village in Lower Saxony, Germany.

Siegelsum is mentioned in a document from 1450, a contract for the sale of land known as Sygildsum.

In a contract from 1475, the priest Hero seals to Sigelsum and in an income register of the parishes in Friesland from the same year, Sigelum is also listed.

In a map made by engineer Johann von Honaert in 1674, the place is listed as Sygelsumb and the district administrator Cirk Heinrich Stürenburg calls it Siegelßum several times in his 1735 description of the Aurich district.

[1] The small village of Siegelsum already had a church in the 13th century, which had to be demolished due to damage sustained in the Thirty Years' War.