Santa María Suamca was a cabecera with visitas at San Lázaro and San Luis Bacoancos. The Santa Cruz River flowed past the mission and it was approximately thirty miles southeast of Guevavi near the town of Lochiel.
Father Ignacio Xavier Keller was assigned to this mission in 1732. In 1734 the Pimas deserted the mission and fled to the hills because they had heard a rumor that Juan Bautista de Anza was coming to kill them. They returned to the mission later, however. In 1736 and 1737 Keller left Suamca to go on an exploratory journey to the north. Since he was familiar with this area, in 1743 he was assigned to go north and convert the Hopi Indians. On this journey, however, he met with hostile Apaches so he returned to Suamca.
Captain Francisco Elias Gonzalez de Zayas, under the orders of interim Sonora Governor don Joseph Tienda de Cuervo, resettled some of the eastern Sobaipuris to Suamca as a defense against Apache attacks in 1762. Following the Jesuit expulsion, Father Francisco Roche was assigned to Suamca. In the fall of 1768 the Apaches attacked Suamca and stole 37 oxen and 180 head of cattle. The Apaches returned in November of 1768 intent on utter destruction of the mission. They set fire to the Indians' dwellings, the storeroom and Roche's quarters. The Apaches withdrew in the evening following a ten-hour siege leaving Father Roche alive and only five Pimas wounded. The mission, however, was a smoldering ruin. Father Roche retreated to Cocospera following the attack.
Father Antonio de los Reyes on 6 July 1772 submitted a report on the condition of the missions in the Upper and Lower Pimeria Alta. This was his report on Santa María Suamca as translated by Father Kieran McCarty. Note his spelling Suamca.
"This Mission and village at Suamnca was raided by the Apaches in the recent year of 1768. They burned the church and the houses of the Mission and put everything to the sword and flames. By leave of the Apaches, the Father Missionary was saved. He gathered a few men, women, and children together and they fled to the outlying mission station of Santiago at Cocspera. The Missionary is still in residence there at the present time. A church is being built, but the lands of this village are unproductive for lack of water. For this reason, the Missionary Father has urged repeatedly the native Indians of Suamnca to reestablish their destroyed village, which was situated in an extensive valley with good lands for cultivation and farming, five leagues from the Presidio at Terrenate. This is the present state of Mission Santa María at Suamnca. Its natives, counted together with those of the outlying mission station, come to the number of thirty married couples, five widowers, twenty widows, the number of souls in all one hundred ten."