Surely is a girl name. It last appeared in U.S. Social Security records in 2006. Surely first appears in the data in 2005 and reached its peak in 2005 (5 births). The chart below shows how the name has risen and fallen over time.
How popular is Surely? (U.S. births per year)
U.S. births per year, 2005–2006 · hover or tap for the count and national rank · source: U.S. Social Security Administration