The earliest traces of human inhabitation on Estonian territory are connected with the Kunda Culture. These finds come from the Early Mesolithic Pulli settlement site by the River Pärnu and date back to about 9000 B.C. The Kunda Culture received its name from the Lammasmäe settlement site in Kunda in northern Estonia, which dates from earlier than 8500 B.C. The preboreal climate of the 8th millennium B.C. underwent a transition in the next millennium to a warm and dry boreal climate, and a humid, warm Atlantic climate predominated in the Late Mesolithic period. The territory of presentday Estonia was covered by forests, where semi-nomadic communities lived near bodies of water and subsisted by fishing, gathering and hunting. The existence of such subsistence activities is confirmed by diverse tools made from stone, bone and antlers.
Comparative material from Latvia and Lithuania helps to determine the anthropological affiliation of the people who inhabited the area at that time: it is likely that the oldest inhabitants of Estonia belonged to a palaeo-European macro-race. Other finds support the hypothesis that the first people to settle in Estonia came through Byelorussia or Lithuania.
In the opinion of linguist Paul Ariste, several words from the language spoken by the people of the Kunda culture have entered into the Estonian language, for instance words for natural objects (mets [forest,] mägi [mountain,] neem [cape,] oja [stream,] nõmm [heath,] soo [marsh]), fish (haug [pike,] rääbis [whitefish,] koger [carp,] siig [lavaret,] koha [pikeperch]) and parts of the body (nahk [skin,] turi [nape,] rind [chest,] koib [leg,] rusikas [fist,] huul [lip]). The concepts elada [to live,] sugu [kin,] eile [yesterday,] kiitus [praise,] häbi [shame,] hull [insane] show that this was a culture whose understanding of its surroundings was quite elaborate. The word küla [village] offers evidence of a certain established, presumably semi-nomadic, form of collective living. It is likely that the Mesolithic inhabitants of Estonia spoke a single proto-European language. The word meri [sea,] incidentally, spread from that language to the FinnoUgric languages and also many Indo-European languages. The lake names Peipsi and Võrtsjärv and the river name Pärnu also presumably date from the times of the Kunda Culture.