Altmelon is a municipality in the district of Zwettl, in the Austrian state of Lower Austria. It lies in the Waldviertel, the wooded northwestern quarter of Lower Austria, a rural region of rolling hills, forests, and small farming villages near the Czech border.
The municipality is administered from Zwettl, the district's main town, which lies to the south. Like other communities in the district, Altmelon is made up of a small main village together with scattered hamlets and farmsteads, a settlement pattern typical of this part of Lower Austria.
Altmelon is a quiet, rural place rather than a tourist centre. Its economy and daily life are tied to agriculture and forestry, and to the surrounding countryside of the Waldviertel. The area is known for its granite formations, ponds, and walking and cycling routes through the woods, though Altmelon itself remains a small, little-visited municipality.