The inscription on the Hillersjö stone, which is 2.8 by 1.0 meters, consists of runic text in the younger futhark that is carved on an intertwined serpent. The main text is written on the serpent with extraneous information, such as the fact that "Þorbjôrn Skald carved the runes," carved outside of the serpent. The inscription is classified as being carved in runestone style Pr4, which is also known as Urnes style. This runestone style is characterized by slim and stylized animals that are interwoven into tight patterns. The animal heads are typically seen in profile with slender almond-shaped eyes and upwardly curled appendages on the noses and the necks. The runic text indicates that Gerlög married with Germund when she was very young, and they had a son who is not named. Germund drowned and the son died. Then Gerlög remarried with Gudrik and they had several children, but only one survived, who was named Inga. Inga married Ragnfast of Snottsta and they had a son who is not named. Both Ragnfast and the son died and so Inga inherited the estate Snottsta. Inga then married Eric, but both soon died without leaving any children. This meant that Gerlög inherited her daughter's property. It has been noted that the chain of inheritance documented on the Hillersjö stone, including how property passed to women through their children, is consistent with the inheritance rules later codified in the 1296 Uppland Law. This text is completed with information from runestone U 20/U 21, where it is said that both Gudrik and Eric had died. The estate Snottsta still exists. At Snottsta and the neighboring Vreta there are several other runestones that complete the saga of Inga that are called the Snottsta and Vreta stones. The runic text begins with the imperitive Rað þu! which is translated as "Interpret!" Other runestones with similar imperitive exclamations in their runic texts include U 328 in Stora Lundby and Sö 158 in Österberga. On the Hillersjö stone, Rað þu! is carved on the eye of the serpent, perhaps indicating that the stone as a record of inheritance was intended for the public. The inscription is signed by the runemaster Þorbjôrn Skald, who also signed the runestone U 532 at Roslags-Bro. Other inscriptions have been attributed to him, including several stones signed only with "Þorbjôrn." He was likely selected as the runemaster for his composition of the Hillersjö stone's text in alliterative verse known as höjningar, a traditional style which uses half-lines characterized by two stressed and accented or rising syllables. The Stockholm County Museum presents the story of Gerlög and Inga as a dramatic real life family saga which was documented for posterity on this runestone sometime between 1060 and 1100. Local theater associations nearby have conducted plays which recreate the rather dramatic tale of Gerlög.
