County Vital Records – Quick Reference from IAGENWEBBirth, death, and marriage records chart with links showing date ranges for each county that has these records and the date ranges for each – some of the earliest go back to 1835.
When you click on a specific county page – note that they are each organized differently – some you will need to scroll down for more links and others have links in a sidebar that lead to additional pages of information.
Many of the Iowa GenWeb county pages either transcribed their vital records, or provide information on where researchers can get copies or view the originals.
If you need an actual copy of the original certificates/records, and they pre-date 1880, check with the County Recorders office. You may also be available to view records in-person at the State Historical Society of Iowa and the Iowa Genealogical Society as both libraries have microfilm copies of vital records.