This study examines the determinants of fertility control in a frontie
r population made up largely of German-Americans during the years from
1850 to 1910. The analysis employs a complex register of population c
onstructed from census enumerations, civil and ecclesiastical vital re
gistration, and tax assessment rolls. The article begins with a series
of bivariate analyses with cohort of mother's birth, religion, ethnic
ity, and husband's occupation determining marital fertility. The secon
d half of the paper presents a multivariate model of the determinants
of fertility using these and other demographic characteristics as inde
pendent variables. The conclusions emphasize the importance of the ove
rall trend toward fertility decline in the United States, as well as t
he role of religion and of occupational differences, in determining ch
anges in fertility behavior in the population of Gillespie County, Tex
as.