Brookside Cemetery is located at the south end of Third Street near the southeastern corner of the original town of Dayton. The street dead-ends at the cemetery. A steep drop-off to Palmer Creek below constitutes its southern border. Highway 221 borders the east side of the cemetery; an open field borders the west side. A forest of deciduous trees and conifers delineate the south and east edges. The cemetery rests on land first used in 1846 for the burial of Riley Smith (Marker 04.16), the son of Andrew D. and Polly Smith. In 1849, Riley’s brother, Almond, was also buried here (Marker 04.15). Both of these burials precede the date of 1850 which is given as the date Joel Palmer donated the land for use as a cemetery. It is surmised that prior to Palmer’s acquisition of a portion of Andrew Smith's Donation Land Claim (DLC) in 1850, the Smith family had used the area as a family burial ground. Andrew Smith, on whose original DLC (#47) the cemetery is located, was the older brother of Riley and Almond. In 1874, Palmer officially deeded the cemetery to the Dayton School District, the only governmental body in the community at the time, as the City of Dayton wasn’t incorporated until 1880. The deed specified that anyone in the community could be buried in the cemetery for free.

A number of pioneers, early Oregon notables, and members of Oregon's first provisional government are buried in Brookside Cemetery. The graves of Medorem Crawford (1819-1891) (Marker 04.02), Francis Fletcher (1814-1871) (Marker 09.06), and Pleasant Armstrong (1810-1853) (Marker 04.18) have all been specially marked by the Daughters of the American Revolution (DAR), with the following badge: "To honor one of those patriots who on May 2, 1843 founded the provisional government at Champoeg, Oregon." Brookside Cemetery is also the final resting place of Joel Palmer (1810-1881), Superintendent of Indian Affairs for the Oregon Territory, co-founder of the City of Dayton with Andrew Smith, and State Senator (Marker 08.14); Stephen Coffin (1807-1882), an early promoter of Portland (Marker 13.10); and Andrew D. Smith (1792-1852), a DLC settler southwest of Dayton and father of Andrew Smith, the co-founder of the City of Dayton with Joel Palmer (Marker 04.20). Christopher Taylor (Marker 06.22), a close associate of Palmer's, the leading merchant in Dayton's early years, and the first Free Mason initiated on the West Coast, is also buried at Brookside.

Through the years new burials were handled by the School District’s deputy clerk. The schools in Dayton used the cemetery to teach state and local history, as well as for community service projects. From the 1950s through the 1970s, Dayton Junior High students performed an annual clean-up at the cemetery before Memorial Day. The cemetery was officially closed to burials in 1956 (or soon thereafter). However, the last interment in the cemetery dates to 1987, via petition by Janice B. Gabriel, bringing the total number of burials to 560. There were several attempts to organize a “friends group” for the cemetery after the School District stopped using the property as a teaching tool. Lack of maintenance and vandalism took a toll on the cemetery. Daytonians were in a disgruntled mood over the cemetery condition, based on letters from the 1980s and 90s in the Association’s files. In 1993, Dayton’s mayor, Jo Windish, set up the Brookside C.A.R.E. group for the purpose of brush clearing, headstone cleaning, and general maintenance. As with many friends groups, the organization fizzled out over time.

In 2015, Kim Courtin and Mike Imlah crossed paths and discovered a mutual interest in cemetery preservation and historical research. Kim and Mike approached the Dayton school board about rebooting the Brookside Cemetery Association. They attended school board meetings and gained the board’s approval for their endeavors. They gathered together a group of like-minded individuals in the community, reactivated the Association in 2016, and brought the cemetery group through to the present day. Before local governments were established in many small towns the local school district was sometimes recognized as a government of sorts. Occasionally schools would end up owning cemeteries and other properties in town – sometimes without their knowledge. In modern times, school district ownership of cemeteries is rare in Oregon with only a few cemeteries still being owned by school districts.

The City, as a Certified Local Government (CLG), with the help of the Association, obtained a matching grant from the State Historic Preservation Office (SHPO) in 2017 to restore grave markers, create a new information sign, inventory the markers in the cemetery, and to create this 10-year preservation plan for the cemetery. In July 2018, the Oregon Commission on Historic Cemeteries (OCHC) held their quarterly meeting in Dayton and held a day-long gravestone restoration workshop at the cemetery. The city became interested in gaining ownership of the cemetery, and the Dayton School District wished to donate the property, so the they worked together to develop a donation agreement to facilitate the transfer of ownership. In November of 2018 the Dayton City Council passed Resolution 18/19-7 which solidified the transfer of ownership of Brookside Cemetery to the City of Dayton.

Since the initial repair and restoration project, Dayton’s Historic Preservation Committee has made Brookside a priority for additional grant-funded projects. The 2019-2020 CLG grant cycle focused on implementing parts of the preservation plan including: the removal of diseased and dangerous trees and limbs (i.e. 'widow-makers'), restoring water to the site, installing 'dusk to dawn' sign, installing 'danger - falling monuments' sign, completion of a care taking workshop for Public Works staff, removal of ivy and bushes to allow clear vision to the cemetery from the road and more. Most significantly is that every "high" and "medium" priority marker in Brookside has been repaired/re-leveled or both. At the end of 2019-2020 grant cycle, a total of 121 markers had been treated. When you gaze across the horizon of Brookside now, the site seems fuller and taller than before.

The City of Dayton and the Historic Preservation Committee are incredibly pleased to have been able to help preserve this landmark to honor the pioneers or our past and to inspire the Daytonians of tomorrow.