SR 28 was added to the state highway system in 1915 as sections of two major highways: the relocated
Sunset Highway from
East Wenatchee to
Quincy and the new
North Central Highway from Quincy to
Davenport. The state took over existing county roads along the route of the
Great Northern Railway, which was built in 1893 to connect
Everett to
Spokane. In 1919, the Sunset Highway was moved further north and the East Wenatchee–Quincy section was transferred to the Chelan and Okanogan Highway, which continued north to
Chelan and
Okanogan. The 1923 legislature established a numbering system for state highways, designating the North Central Highway as State Road 7 and Chelan and Okanogan Highway as State Road 10. The Wenatchee–Quincy highway was fully completed in 1926, using $200,000 in state appropriations (equivalent to $ in dollars) and replacing an earlier road-and-ferry on the west side of the river.
Macadam paving of the North Central Highway began in 1927, as part of an accelerated push for improving cross-state highways, and was fully complete by the end of 1930. Both highways were fully paved by the late 1930s and designated in 1937 as
Primary State Highway 10 (PSH 10) from East Wenatchee to Quincy and
PSH 7 from Quincy to Davenport. SR 28 was established during the
1964 state highway renumbering, with instituted a system of sign routes (now state routes) to replace the earlier system of primary and secondary highways by 1970. It replaced the East Wenatchee–Quincy section of PSH 10, with the rest absorbed into
US 97, and all of PSH 7 except for the Quincy–George section, which became
SR 281, a child route of SR 28. In the early 1960s, business groups in Grant County had unsuccessfully sought to move
US 2 or a designated
alternate route to the corridor that would later become SR 28. The
Washington State Highway Commission, chaired by a state senator from Ephrata, endorsed the proposal based on the higher traffic volumes compared to the US 2 corridor through
Waterville, but the renumbering was denied in 1963 by the route numbering committee of the
American Association of State Highway Officials. The highway was extended further north through East Wenatchee in 1975 after US 2 was rerouted onto the newly-completed
Richard Odabashian Bridge. In the 1980s and 1990s, government officials in East Wenatchee proposed the construction of a
parkway along the Columbia River to replace a section of SR 28 with a wider, modern highway. The proposal was shelved due to opposition from local residents and potential impacts on the environment. Parallel to the riverfront proposal, Wenatchee officials announced plans for a four-lane freeway replacing of SR 28 and SR 281 between Wenatchee and
George in 2000. The $430 million project (costing equivalent to $ in dollars), which would have connected Wenatchee to Interstate 90, was rejected by the state government due to the need to fund more urgent projects in the
Puget Sound region. Traffic congestion on the urban sections of SR 28 had grown considerably by the early 2000s, leading to WSDOT publishing new traffic studies and project plans for the corridor. The
SR 285 interchange in East Wenatchee was identified in a 2002 study as in need of a near-term rebuild and long-term conversion into a
single-point urban interchange. The interim configuration, comprising a southbound bypass roadway with several ramps, was constructed between 2011 and 2013 at a cost of $28 million. The original intersection, now serving northbound traffic, was replaced with a
roundabout in August 2017. A long-term plan adopted in 2006 proposed widening the East Wenatchee section of the highway to four lanes by 2025 to meet projected demand from a larger regional population. The plan also included an extension of Eastmont Avenue to the US 2 and US 97 intersection, functioning as a bypass of East Wenatchee. The widening of SR 28 between 9th and 19th streets, estimated to cost $58 million, was funded by the legislature in 2015 and is scheduled to begin construction in 2024. ==Major intersections==