U 15 is located inside Ekerö church. It was previously part of the stone floor in the church but has since been put on display. It is assumed that Ingeborg lived at old Asknäs estate that is located close to the church. The stone is also referred to as the Ingeborg-stone. Although the stone uses the rune alphabet, the inscription itself is in Latin.

Uppland Runic Inscription 15
Created	12th century
Discovered	Ekerö, Uppland, Sweden
Rundata ID	U 15
Text – Native
Latin : Ingeborg filia Ermundi iacet hic
Translation
Ingeborg, daughter of Ermund rests here