The halflings, like the other "Little people" races of the gnomes and dwarves, originally hail from the continent of Maundelay, which is located far southeast of Ashra (And Nessene as well). A check of the description of Maundelay and a glance-over of the maps may give you some ideas.
While Nessene may have started as a wilderness lived in only by the Gatekeepers and the descendants of the Veyran Vanguard, it has grown somewhat. Many choose to raise their families on the island, either in one of the larger cities, one of the medium interior settlements, or in smaller shires and villages not listed on the map. You may hail from either Maundelay originally, or your family may have raised you on Nessene.
Population wise, Nessene is composed of the following ratio of inhabitants: 70% human, 10% elf, 5% half-elf, 5% half-orc, 4% dwarf, 3% gnomes, 3% halflings.