Hi Howard,
I looked in the telephone white pages for distribution of the name and of
over 300 Kielhorns, there's only 3 listed in Kiel
I also looked to see if there was mention of any Kielhorn, (either migration
or domestic records) on this site, but most of the online references are for
Hannover : http://aidaonline.niedersachsen.de/
Good luck,
Rena in England