The biggest lakes form the spine. The Sneekermeer near the town of Sneek hosts the annual Sneekweek, the highlight of the Frisian sailing calendar. The Tjeukemeer, southeast of Joure, is the largest single body of water in the system. Then there are the Heegermeer, the Fluessen, the Slotermeer, the Groote Brekken, and a long tail of smaller lakes and pools, the Brekken and Wielen and Poelen that carry the Frisian vocabulary for different kinds of water. Most of this region belongs to what locals call the Zuidwesthoek, the southwestern corner, an area with its own Frisian dialect. The municipalities of Súdwest-Fryslân and De Fryske Marren occupy most of the territory.

If you arrive by boat, and most Dutch visitors do, plan around the bridges. The lakes are stitched together by canals, and the canals are interrupted by an army of man-controlled bridges that operate during regular hours. Miss the opening window and you wait. Bring a paper chart along with the GPS; the channel markers in the smaller waterways are easy to misread from a phone screen. Train travelers reach the region via Leeuwarden, with regional Arriva services running south to Sneek and on to Stavoren. Bus connections cross the Afsluitdijk from North Holland. The nearest airports are Schiphol and Groningen Airport Eelde, both at some distance, which means the lakes have escaped the kind of weekend-tourist saturation that hits the Dutch coast.

Hindeloopen, IJlst, Lemmer, Sloten, Stavoren, Workum. The names roll off in clusters because the towns sit close together, each one a tight little historic center wrapped in defensive water. Hindeloopen has a distinctive painted folk-art tradition. Sloten still keeps its star-shaped fortifications. Lemmer holds something genuinely extraordinary: the D.F. Wouda Steam Pumping Station, the largest still-operating steam-powered pumping station in the world, designated a UNESCO World Heritage Site. It was built in 1920 to drain the polders of southwestern Friesland, and it still fires up when the water gets high. The hiss of steam and the rhythm of enormous reciprocating engines is not something you usually associate with a heritage site, but here it is, working as it was built to work.

Sneekweek is the moment the whole region tilts toward Sneek. Held every August, the regatta is the largest sailing event on inland waters in Europe by some measures, a week of racing in the traditional Frisian classes alongside more modern keelboats. Prices for rooms anywhere on the lakes rise sharply in that week. The traditional skûtsje, a flat-bottomed Frisian sailing barge that once carried peat and freight across these waters, now races in the Skûtsjesilen series that runs through the summer. German and British amateur sailors have started to discover the lakes in growing numbers, drawn by the combination of protected water, generous wind, and a culture that takes boats seriously. The locals notice and welcome the visitors. They also keep using the Frisian names.