Moyahua Parish was created from Juchipila Parish in 1808. Parish records for Moyahua are available starting in 1813 (Padron), and baptism, death, and marriage records begin in 1814. Other areas to look for Moyahua families is in Juchipila, Mezquital del Oro, Cuxpala, Santa Rosa, and Apozol (Aposol) records. I also have found some Moyahua and Juchipila connections in Jalpa (Zacatecas). When Moyahua was split from Juchipila in 1808, some family territories were located in both Juchipila and Moyahua parishes, so it is possible to find families in both areas. It is located on several Nova Hispana maps dating back to 1636 under the name Moyauan.
The area known as Moyahua is very old, and in addition to the maps mentioned above, Moyahua is mentioned in various written records dating from the mid 1600's, and likely much further than what I have came across.