In 1862, a flood pierced another opening, the Thyborøn Channel, through the remainder of Agger Tange (see satellite image). Agger Channel was continuously filling with sand and eventually closed in 1877. Since then, the remaining Thyborøn Channel has been kept open and navigable by dredging. The harbour of Thyborøn was built in 1914–1918 and a town was founded. The two isthmuses have shifted eastwards since the 1800s. They have only been preserved by groynes, persistent sandpumping and two road dams along their inward (eastern) side.