The commune is situated in the southeastern foothills of the Bodoc Mountains [ro] in the Eastern Carpathians, at an altitude of 589 m (1,932 ft), on the banks of the river Dalnic.

Dalnic is crossed on its south side by national road DN11 [ro] (part of European route E574), which starts in Brașov, passes through Târgu Secuiesc and Onești, and ends in Bacău.

György Dózsa (1470–1514) a Székely man-at-arms set out from here in 1514 on the crusade announced by cardinal Tamás Bakócz which ended up in a peasant war.

In August 1940, under the auspices of Nazi Germany, which imposed the Second Vienna Award, Hungary retook the territory of Northern Transylvania (which included Dalnic) from Romania.

Towards the end of World War II, however, the commune was taken back from Hungarian and German troops by Romanian and Soviet forces in September 1944.