Blå leden (lit trans: the blue trail) starts in Vaxholm harbor and stretches approximately 36km to Domarudden in Österåker municipality. The start and finish is marked by a huge anchor in Vaxholm harbor and the last/first blue marking close to the café in Domarudden. Along the way it passes Bogesund castle, Rydbo and the outskirts of Åkersberga. It is mostly moderate to easy trails with a few longer segments of gravel road and some shorter paved sections. It is mostly well marked with blue paint on trees along the trail but there are some longer sections in the Rydbo forrest who have next to no markings. The trail has been used for many years in the local Blåfrusen ultramarathon (lit trans: Frozen blue ultramarathon) the used to run each year in December.
The Vaxholm segment is described here: https://naturkartan.se/sv/vaxholm/vandringsleden-bla-leden