Mt. Greenwood still votes around 55% Republican in Presidential elections and is definitely the largest Republican-voting neighborhood within the city of Chicago. There are some Republican pockets along the border with Lincolnwood also in the neighborhoods of North Park and West Ridge, though those neighborhoods are overall Democratic; I think there are a lot of Orthodox Jews there.
Yet Mt. Greenwood is heavily Democratic when it comes to voting for Dan Lipinski. Very interesting part of town! Similar in many ways to Bridesburg in Philly or Morrell Park in Baltimore or some of the Russian areas of Brooklyn. White Ethnic, blue collar areas, usually kinda geographically isolated, known for racial tensions, have swung heavily Republican in recent years.