http://dictionary.reference.com/browse/lobby says 1808 >
Political sense of "those who seek to influence legislation" is attested 1808 in Amer.Eng., in ref. to the custom of influence-seekers gathering in large entrance-halls outside legislative chambers. The verb in this sense is first attested 1850. Online Etymology Dictionary, © 2010 Douglas Harper
http://www.merriam-webster.com/dictionary/lobbyist says 1837
1847 willard opened
1869-1877 Ulysses S. Grant president
1928 hay adams opened