It includes the communities of Bellevue, Boya, Greenmount, Guildford, Hazelmere, Helena Valley, Jane Brook, Koongamia, Midland, Midvale, Stratton, Swan View, Viveash, Woodbridge, as well as parts of the communities of Darlington, Middle Swan, Red Hill, and South Guildford.

A redistribution ahead of the 2008 election made Midland slightly more secure for Roberts, and she was reelected even as her party narrowly lost government.

In 2013, however, Roberts was nearly defeated by Liberal challenger Daniel Parasiliti, with only Green preferences allowing her to survive by 24 votes.

Roberts saw off Parasiliti with somewhat less difficulty in a 2017 rematch as her party regained government on the strength of a strong showing in Perth, picking up enough of a swing to make Midland a safe Labor seat in one stroke.

She consolidated that swing in 2021 amid the massive Labor wave that swept through the state that year, and now sits on a margin of 25.5 percent.