No. Finsbury Park is 2.9 miles (17 minutes' drive) from the northernmost point of the Congestion Charge which is Pentonville Road.
London's congestion charge zone currently covers the following areas:
City of London
parts of Marylebone, Lambeth and Southwark
Check out the Congestion Charge zone map at Londonandpartners.com.
The Congestion Charge applies to most vehicles entering Central London. As you enter the zone, you will see a large letter "C" in a red circle.
Make sure you know how it might affect your visit. Find out the how, when, where and what of the Congestion Charge in the traveller information at Visitlondon.com.