The Rapperswil Seedamm is the artificial causeway at the narrowest area of Lake Zurich between Hurden (SZ) and Rapperswil (SG). The structure contains two bridge segments and is approximately 1 kilometre (0.62 mi) long. The Seedamm carries a road (Hauptstrasse 8) and a railway across the lake, with the railway being used by the S5 and S40 services of Zürich S-Bahn and by Südostbahn's Voralpen Express.
The Melide causeway across a narrow section at Lake Lugano is comparable to the Seedamm.