Groote Zeesluis

Groote Zeesluis is a lock and bridge complex near Muiden comprising three chambers with the main lock measuring 49 meters long and 7.6 meters wide. The structure allows boat traffic to pass between the inland Utrecht Vecht waters and the broader IJmeer.

Built in 1672, the lock was part of the Dutch defense system against floods from the former Zuiderzee sea. It served as part of the Old Dutch Water Line, a defense strategy that used water barriers to protect the region.

The lock connects the Utrecht Vecht to the IJmeer and is used daily by boat traffic and locals navigating between these two water systems. This working structure shapes how people experience the waterways connecting inland communities with the broader region.

Visit on a weekday or Saturday when you can watch boats passing through and see the lock in active use. The site is easy to access from nearby paths and viewpoints along the waterside, giving you good views of the entire structure.

The structure retains original wooden components from the 17th century, making it a rare example of preserved water engineering from that era. These original parts continue to function, showing how well Dutch engineering held up over time.