In the U.S. Senate, the State of Ohio is represented by Senators Rob Portman (R) and Sherrod Brown (D).
http://www.portman.senate.gov/public/
http://www.brown.senate.gov/
Lake County is within Ohio's 14th U.S. Congressional District. It is currently represented by David Joyce (R - Russell Township).
http://joyce.house.gov/
Lake County encompasses two districts of the Ohio House of Representatives. District 60 to the north is represented by John M. Rogers (D), and District 61 to the south is represented by Jamie Callender (R).
http://www.ohiohouse.gov/john-m-rogers
http://www.ohiohouse.gov/jamie-callender
Lake County is part of two Ohio Senatorial districts. To the north, District 25 is represented by Kenny Yuko (D), and to the south District 18 is represented by John Eklund (R).
http://www.ohiosenate.gov/yuko
http://www.ohiosenate.gov/eklund