Make iTerm2 window history larger In iTerm2 3.1.5 on macOS High Sierra, I want to be able see more of my history as I scroll. Currently the scroll history is not enough for me. How can I increase the amount of data history I see while scrolling upwards?

I tried looking in iTerm2 preferences and changing the magic section for instant replay (on the general tab) but that's not doing it.
You have to set the scroll back buffer.  This option is found under Profiles >> Terminal.

You can either set the number of lines in the buffer to the number of lines you want to scroll back, or check the box for "unlimited scrollback".