National Census Records
No true national census exists for Spain. The closest collection that could be considered a national census is the Marques de Catastro de Ensenada (Catastro). The Catastro was taken for tax purposes between the years 1749 to 1756. The census included the kingdom of Castille and Leon. FamilySearch microfilmed the Catastro where available in the historical provincial archives throughout Spain.
FamilySearch is currently working closely with Spain's Minisiterio de Cultura to convert the microfilms to digital images. The Ministerio de Cultura has published the section called Respuestas Generales on their website, found at: http://pares.mcu.es.
FamilySearch has also began publishing the Catastro on it's website too. Besides the Respuestas Generales, FamilySearch is publishing all other sections that they originally microfilmed. Those sections are:
- Autos generales
- Bienes de legos o seglares
- Bienes de eclesiásticos
- Personal de eclesiásticos
- Respuestas generales**
- Memoriales de legos o seglares
- Memoriales de eclesiásticos
Local Census Records
Local municipalities (municipios) took censuses of their populations periodically. In Spain you will find that the majority of the municipios began taking population censuses in the latter half of the 19th Century and continuing onto the present time.
Municipal census records are usually housed in the Municipal archives. Some have been microfilmed by FamilySearch (see Cádiz), but most have not. The best place to find local census records is through the Directorio de Archivos. Perform a search for the municipio where your ancestor's lived.
You can review the census records for Castilla La Mancha online at this site: padrones1808.jccm.es/
16th Century Census Records
Dr. George R. Ryskamp published a wonderful article on 16th Century Spanish census records in the fall issue of the 2002 BYU Family Historian.