From the On Course Dictionary:
links Seaside golf course constructed on a natural sandy landscape that has been shaped by the wind and receding tides (from the Old English “hlincas”, meaning the plural of a ridge, a Scottish term to mean the undulating sandy ground near a shore ); also used more generally as a synonym for a “seaside golf course” and sometimes for a golf course that is configured with nine holes extending outward and nine holes returning to the clubhouse, although there is no factual basis for such use; often incorrectly used to describe any golf course
linksland Land located proximal to an open sea, or bay that is connected directly to an open sea, and which possesses the characteristics of naturally rolling sand dunes or land features formed by the wind, the ocean and the receding tides; whether the land is traversed by a river or estuary associated with the land is superfluous and it may be noted that the presence of a river or other tributary or body of water differing from an ocean or sea is in and of itself not justification for land to be called bona fide linksland; land approximating linksland in this event is, in slang, “links-ish” in nature, but clearly not true linksland