Hungary (972 km2) Moson (German: Wieselburg, Slovak: Mošon) was an administrative county (comitatus) of the Kingdom of Hungary, situated mostly on the right (south) side of the Danube river.
Its territory is now divided between Austria and Hungary, except a small area which is part of Slovakia.
Moson is also the name of a town, nowadays part of the city Mosonmagyaróvár, Hungary.
In 1920 by the Treaty of Trianon a tiny part of Moson county close to Pressburg (Pozsony, today's Bratislava) became part of newly formed Czechoslovakia.
Three villages – Dunacsún, (Čunovo), Horvátjárfalu (Jarovce), and Oroszvár (Rusovce) – became part of Czechoslovakia.