Astarac borders Armagnac to the northwest, the Rivière-Basse and Bigorre to the west, the Magnoac to the southeast, and Comminges to the east. Its principal cities are Mirande, Masseube, Miélan, Tournay, Pavie, Idrac-Respaillès, Castelnau-Barbarens, Berdoues-Ponsampère, Mont-d'Astarac, Miramont-d'Astarac, Laas d'Astarac, and Fontrailles.

Counts

• 926 – 960 Arnold I Nonat
• 960 – c.1000 García, son
• c.1000 – 1023 Arnold II, son
• 1023 – 1040 William I, son
• 1040 – 1083 Sancho I, son
• 1083 – ???? William II, son
• ???? – 1142 Bernard I, brother
• 1142 – 1174 Aznar Sancho I, son, co-ruled with brother
• 1142 – 1174 Bohemond, brother, co-ruled with brother, sole count 1182 – 1183
• 1174 – 1182 Bernard II, nephew
• 1183 – ???? Marquesa, cousin, co-countess
• 1183 – ???? Beatrice, sister, co-countess
• ???? – 1233 Centule I, son
• 1233 – 1249 Centule II, son
• 1249 – 1291 Bernard III, brother
• 1291 – 1300 Centule III, son
• 1300 – 1324 Bernard IV, son
• 1324 – 1326 Bernard V, son
• 1326 – 1331 Amanieu, brother
• 1331 – 1368 John I, son
• 1368 – 1410 John II, son
• 1410 – 1458 John III, son
• 1458 – 1511 John IV, son
• 1511 – 1569 Martha, daughter

Hereafter also count of Candale and Benauges:

• 1511 – 1536 Gaston, husband
• ???? – 1528 Charles, son
• 1528 John I, brother
• 1528 – 1571 Frederick, brother
• 1571 John II, son
• 1571 – 1572 Henry, son
• 1572 – 1593 Margaret, daughter