|Coordinates (Joniec): Coordinates:|
|• Total||72.64 km2 (28.05 sq mi)|
|• Density||36/km2 (93/sq mi)|
Gmina Joniec is a rural gmina (administrative district) in Płońsk County, Masovian Voivodeship, in east-central Poland. Its seat is the village of Joniec, which lies approximately 14 kilometres (8 mi) east of Płońsk and 50 km (31 mi) south-east of Warsaw.
The gmina covers an area of 72.64 square kilometres (28.0 sq mi), and as of 2006 its total population is 2,613 (2,614 in 2013).
Gmina Joniec contains the villages and settlements of Adamowo, Joniec, Joniec-Kolonia, Józefowo, Krajęczyn, Królewo, Ludwikowo, Nowa Wrona, Omięciny, Osiek, Popielżyn Górny, Popielżyn-Zawady, Proboszczewice, Sobieski, Soboklęszcz, Stara Wrona and Szumlin.