Are Infection maps in Custom games?

I want to go in Infection maps to explore the weapons but if I try it in the actual game I’m dead and I can’t find it when I try custom games, am I just looking in the wrong place for them or are they just not there?

The Infection maps should be under the “343 Industries” tab when you want to pull up a map.

Yeah you can find them just follow the advise of HaXoR73. Plus you can bookmark more, from the custom browser.