#ElectionTwitter Map of which Democratic Presidential Candidate got the highest % of the vote in each county, from 1972-2016. Carter's run in 1976 (colored red) achieved the highest Democratic % in the most counties, 2,010 in total, many in areas that are very conservative today. 
If we focus on the modern Dem coalition by taking out Carter's runs, most counties highest Dem % comes from one of: Obama's run in 2008 (which did well in more liberal areas), Clinton's runs in 1992/1996 (strong in the South), & Dukakis' run in 1988 (areas hit by the Farm Crisis)
Here's the best performing Democratic Presidential Candidate by State from 1972-2016. Carter's run in 1976 & Obama's 2008/2012 runs achieved the highest Democratic % in the most states, except for: CA (Clinton 2016), MA (Kerry 2004), AZ/LA (Clinton 1996), & IA (Dukakis 1988).
If we start the clock at 1984, Obama's 2008/2012 runs look even more impressive: he got the highest % of any Dem in 33 of 50 states & in DC. Bill Clinton's 1996 run got the highest % in 8 states, Dukakis' 1988 run in 7 states, & Hillary Clinton & Kerry in 1 state each (CA & MA).
Since it was requested& I always forget to include it, zoom-in on NYC area: teal = Clinton 2016 (strongest in Manhattan/Westchester), light blue = Obama 2012 (not Obama 2008! he was stronger in 2012 in Brooklyn, Queens, Bronx. Sandy bump?), yellow = Gore 2000 (Staten Island)
