Cook Hollow is a

valley A valley is an elongated low area often running between Hill, hills or Mountain, mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers ...

in Oregon County in the U.S. state of

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

. Cook Hollow most likely has the name of a local family.

References

Valleys of Oregon County, Missouri Valleys of Missouri {{OregonCountyMO-geo-stub