There are over one million school-age children in Missouri, and we estimate 61,000 (6% of all school-age children) are homeschooled. Missouri is one of 29 states that does not require homeschooling to be reported. Using methods that can be replicated elsewhere with publicly available data, we test three approaches to estimating homeschool participation: using American Community Survey (ACS) data; subtracting public and estimated private school counts from ACS school-age totals; and polling parents. We comment on the usefulness and limitations of each approach and provide a model for researchers seeking to estimate homeschooling trends in states that lack administrative data.