Land Grants in Nueva Galicia during the XVII century

From the moment I started researching the history of Aguascalientes, I realized that most of the large haciendas owned by our ancestors were land grants (mercedes de tierras) awarded by the Spanish crown to the early settlers and those who participated in que conquest of Mexico. Land grants were intended to promote agriculture, cattle breeding and mining in the area.

What I would like to know is where documentation on the early land grants is archived. Is it at the Archivo General de la Nación in Mexico City, at the Archivo Histórico de Nueva Galicia in Guadalajara, or at the Archivo General de Indias in Seville? I would like to know if Lope Ruiz de Esparza's "Estancia de Morcenique" was a land grant or if he actually purchased it from someone else. Lope was one of the early settlers of Aguascalientes. Other haciendas and ranches of interest are "San Bartholome" (aka San Bartolo) owned by Luis Tiscareño de Molina, Estancia de "El Agostadero" owned by Pedro Fernández de Vaulus, Labor de Chapultepeque" owned by Miguel López de Elizalde, "San Lorenzo" owned y Juan Bautista Ponce, "San Gerónimo" owned by Gerónimo de Orosco, "La Ciénega de Xiconaque" owned by Christóbal Lozano, Labor de "Los Gallos" owned by Pedro Macías Valadez, "Estancia de San Jacinto del Rincón" owned by Vicente Zaldívar y Mendoza, "El Picacho" owned by Salvador Ruiz de Esparza, etc. etc.

Any information will be greatly appreciated.

Bill Figueroa