59°34′15″N 17°57′30″E / 59.57083°N 17.95833°E
The Hargs bro runic inscriptions, or U 309, U 310 and U 311, are 11th century Younger Futhark inscriptions in Old Norse on bedrock in Skånela Parish, Uppland, Sweden.
U 309 and U 310 constitute a twin monument in the style Pr4 and they are thus dated to the period 1060–1100. They belong to a group of c. 20 runestones called the Jarlabanke Runestones that are connected to the local strongman Jarlabanke and his clan. Together with the Broby bro Runestones and the Uppland Rune Inscriptions 101, 143 and 147 these particular runestones, however, treat the female matriarch of the clan called Estrid.
U 310 tells that Estrid had a husband named Ingvar, and he had a son prior to marrying Estrid, named Ragnvald who died. Estrid constructed a bridge, apparently a tradition in her family.
U 309 mentions Sigvid, Ingvar and Jarlabanke in a way that suggests that they are Estrid's sons. This Jarlabanke is not the same one as the Jarlabanke who raised the runestones in Täby, because he was the son of an Ingefast and a Jorun.
These runestones show a peculiarity to this family: the sons often have the same name as their fathers.
Estrid is the same person as the Estrid who is mentioned on a number of runestones in Täby and other locations (the Broby bro Runestones and Uppland Rune Inscriptions 101, 143 and 147). This Estrid was the maternal ancestor of a great clan called the Jarlabanke clan, and she was the maternal grandmother of the powerful Jarlabanke who claimed to own all of Täby.
The carver of the Snottsta runestone called U 329, where an Estrid and her brother Ragnfast are mentioned, is believed to be the runemaster named Fot who also made the runestones for the Jarlabanke clan. This strongly suggests that Estrid was born in Snottsta (also spelled Snåttsta), married Östen of Täby and married for the second time in Harg near Snottsta.