At the start of the
Mexican–American War in 1846, citizens of the United States were ordered to evacuate Tampico. Franklin Chase signed his property over to Anna to prevent its confiscation by Mexican authorities. He left Tampico in June of that year and she stayed to manage the business, exempt from the evacuation order due to her status as a subject of the United Kingdom. Chase spied on troop movements and collected information on the defenses of the city which she passed along to the
United States Navy via British sailors. Chase also provided
disinformation about U.S. troop strength. Possibly upon learning of Chase's troop estimates, the withdrawal from Tampico of Mexican defense forces was ordered by
Antonio López de Santa Anna. Anastasio Parrodi led his troops out of the city in late October 1846. U.S. Navy commodore
David Conner, who led the
Home Squadron during the war, did not sail for Tampico until after receiving a communiqué from Chase in early November informing him of the withdrawal of the defense forces. Tampico was captured on November 14, 1846. After learning that the U.S. forces had arrived in Tampico, Chase hoisted a U.S. flag over her house. The fortifications of the invading forces were named Fort Ann, after her. For her deeds, she became known as the "Heroine of Tampico". ==Death==