The highway travels north on a four-lane section of 104th Avenue Southeast, passing Kent-Meridian High School and several suburban neighborhoods.

SR 515 then diverts northeast onto 108th Avenue and crosses Harrison Creek, leaving Kent city limits near Panther Lake.

[3] The highway then supersedes a section of Talbot Road and crosses under I-405, which it intersects in a half diamond interchange at the south edge of downtown Renton.

[4] Talbot Road continues into downtown Renton, passing several big-box stores and SR 515 turns northeast onto Grady Way near the city hall.

[3][5] SR 515 is used by King County Metro route 160, which provides bus connections to areas between Kent's train station and Downtown Renton.

[13] Suburban development of the Kent and Renton areas in the 1960s and 1970s brought higher traffic volumes to the highway, necessitating an expansion project.