Forlond was a harbour that lay on the northern shore of the Gulf of Lhûn, in the Elvish land of Forlindon. Its precise location is open to question. In Appendix A to The Lord of the Rings, there's an account of the arrival of the Gondorian general Eärnur in Lindon, where we're told that his ships filled the Forlond. That account strongly suggests that the harbour represented no more than the northern part of Mithlond, the Grey Havens. According to the maps that accompany The Lord of the Rings, though, the Forlond was placed some two hundred miles to the west of the Havens, at the mouth of the Gulf of Lhûn.
Whichever of these alternatives is correct, we can be sure that it lay on the northern shore of the Gulf, because the name Forlond is derived from the Elvish for 'north haven'. It had an equivalent on the southern shore, too: the Harlond or 'south haven'.