I came across this recently. It is the Diccionario geografico-estadistico de España y Portugal published in 1826. It lists thousands of towns and villages and gives their population!

They are in pdf format and are searchable. If you can not find the village you are looking for, check Volume 11, which is a supplement for those places that were missed.

Volume 1: A – Bar
https://books.google.com/books?id=rkkFAAAAYAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Volume 2: Bar – Cas
https://books.google.com/books?id=egpDAAAAcAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Volume 3: Cas - Esp
https://books.google.com/books?id=7P8HAAAAQAAJ&printsec=frontcover&dq=Diccionario+geografico-estadistico+de+Espa%C3%B1a&hl=en&sa=X&ved=0ahUKEwiPvrbc17rgAhUKjlQKHRjIC4kQ6AEIMjAB#v=onepage&q=Diccionario%20geografico-estadistico%20de%20Espa%C3%B1a&f=false

Volume 4: Esp - Hoc
https://books.google.com/books?id=eUoFAAAAYAAJ&printsec=frontcover&dq=Diccionario+geografico-estadistico+de+Espa%C3%B1a&hl=en&sa=X&ved=0ahUKEwiPvrbc17rgAhUKjlQKHRjIC4kQ6AEIYjAH#v=onepage&q=Diccionario%20geografico-estadistico%20de%20Espa%C3%B1a&f=false

Volume 5: Hoc – Mem
https://books.google.com/books?id=AzwFAAAAYAAJ&printsec=frontcover&dq=Diccionario+geografico-estadistico+de+Espa%C3%B1a&hl=en&sa=X&ved=0ahUKEwiPvrbc17rgAhUKjlQKHRjIC4kQ6AEIOjAC#v=onepage&q=Diccionario%20geografico-estadistico%20de%20Espa%C3%B1a&f=false

Volume 6: Mem – Pes
https://books.google.com/books?id=3gpDAAAAcAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Volume 7: Pes – Sol
https://books.google.com/books?id=-wpDAAAAcAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Volume 8: Sol – Ton
https://books.google.com/books?id=EgtDAAAAcAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Volume 9 – 10: Ton – Zuz
https://books.google.com/books?id=ImrCOb1PrmUC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Volume 10: Villa Viciosa-Z.
https://books.google.com/books?id=9dVAAQAAMAAJ&pg=PA79&dq=Diccionario+geogr%C3%A1fico-estad%C3%ADstico+de+Espa%C3%B1a+y+Portugal+tomo+xiii&hl=en&sa=X&ved=0ahUKEwix4Mmv0LrgAhWTAXwKHfVhAXUQ6AEIXzAH#v=onepage&q=Diccionario%20geogr%C3%A1fico-estad%C3%ADstico%20de%20Espa%C3%B1a%20y%20Portugal%20tomo%20xiii&f=false

Volume 11: Supplement A - Z

https://books.google.com/books?id=A-dAAQAAMAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false