Boulder is a boy name. It last appeared in U.S. Social Security records in 2013. Boulder first appears in the data in 2004 and reached its peak in 2004 (5 births). The chart below shows how the name has risen and fallen over time.
How popular is Boulder? (U.S. births per year)
U.S. births per year, 2004–2013 · hover or tap for the count and national rank · source: U.S. Social Security Administration