Homburg is located in the northern part of the Saarpfalz, bordering Rhineland-Palatinate and about 20 km away from the French border. It is 16 km from Neunkirchen and 36 km from Saarbrücken. The villages Beeden, Schwarzenbach, Wörschweiler, Einöd and Ingweiler are situated in or on the Blies valley.
Homburg is composed of nine districts: Beeden, Bruchhof-Sanddorf, Einöd, Erbach, Jägersburg, Kirrberg, Reiskirchen, Schwarzenbach and Wörschweiler.
The Einöd district has three municipal factions: Einöd, Ingweiler and Schwarzenacker; Jägersburg is composed of the fractions Jägersburg, Altbreitenfelderhof and Websweiler; Erbach has Erbach, Lappentascherhof, and Johannishof.