Kammala jumla mai zuwa: An fara tashin hankali tsakanin sojojin Amurka da na Mexico a ranar 25 ga Afrilu 1846 tare da sojojin Mexico da suka kashe da kuma kama wasu sojojin Amurka a jihar Texas ta gaba. Ƙungiyar
Yaƙin Palo Alto, babban yaƙin farko na Yaƙin Mexico da Amurka, an yi yaƙi a ranar 8 ga Mayu, 1846, 'yan mil daga garin Brownsville na zamani, Texas. Sojojin Mexico 3,400 (wani bangare na "Sojojin Arewa") karkashin jagorancin Janar Mariano Arista na Mexico sun yi yaƙi da sojojin Amurka 2,400 a karkashin Janar Zachary Taylor. Sojojin Taylor sun kori 'yan Mexico daga filin. Majalisa ta Amurka ta mayar da martani ga wadannan rikice-rikice ta hanyar ba da sanarwar yaƙi da Mexico a ranar 13 ga Mayu 1846 <unk> Yaƙin Mexico da Amurka ya fara.