Topeiros is a municipality in the Xanthi regional unit, Greece and the seat of the municipality is in Evlalo. The North section of the Municipality is mountainous and composes part of the mountain range of Rodopi. It has rich vegetation, with rare flora and fauna, deep ravines with a big number of small streams which join Nestos river.

The highest top is Imera, with an altitude of 1286 meters. All the west side is traversed by the Nestos river, which has its springs in Bulgaria. Its natural flow creates meanderings, which are surrounded by steeps areas with aquatic vegetation forming a distinctive landscape, known as the "Narrows of Nestos".

The Southern part of the municipality and the biggestone, is flat and covered with arable lands. There are some hilly as well as swampy lands, mostly near the coast line of Thracian Sea and the Nestos Delta. There are also sandy hills near the coast line. A very significant element of the flat part is the Nestos river. It is the western border of the municipality.

The river in its whole length and specifically at its end in the sea, composes the Delta and presents a significant ecological and aesthetic sense, because of the aquatic river side forest all along the river. There are a lot of streams and torrents in the flat parts, with the Laspia torrent, as the most significant one.

Also, the most important natural resources are the Nestos Delta and the Narrows of Nestos. The Delta of Nestos offers a very rich variety of fauna and its water consists a significant agricultural resource.