The French Canadian trappers and the Native Americans called the creek “LaCreole” for its clear rapidly flowing water flowing over the rocks. The game was plentiful. The first wagon train came to this area in 1843 and the first settlement was on the LaCreole. James A. O’Neil built the first gristmill where the LaCreole and O’Neil’s Creek converged. A small community formed around the mill. It was one of only two mills west of the Willamette River. O’Neil offered lodging and a store for visitors who had made the long journey to this mill. Miners on their way to the California Gold Rush would also stop for flour. Two wagon trains had arrived to this area in 1843 and 1844 and began to make their new homes along the LaCreole. The mill flooded out in 1849 and O’Neil sold out to James W. Nesmith and Henry Owen. The mill was rebuilt and named Nesmith’s Mill. It was later sold to Rueben P. Boise, who had an adjoining donation land claim, and the area was renamed Ellen’s Dale after Boise’s wife. Later renamed Ellendale, it hosted the first official post office in Polk County, opening on January 8, 1850.
Cynthian (also Cynthiana, Cynthia Ann) was becoming a small community on the north side of the LaCreole where north Dallas is now located. In 1850, the county seat was formed in Cynthian and the houses of Thomas Lovelady, Carey Embree, and John Lyle were used for holding court. By 1852 the town of Cynthian had been renamed Dallas, after Pres. Polk’s Vice Pres. George M. Dallas. A post office was established and John E. Lyle was the first postmaster. Soon the residents realized the wells were drying up and there was not enough water to continue to grow this little settlement. It was thought that there would be more water available on the south side of the Rickreall.
In 1855, some people realized by creating an Institute for learning on the south side of the creek, that they would assure the development of the town there. A board of trustees was formed with Ruben P. Boise elected President of the Board and Horace Lyman secretary. Solomon Shelton donated thirty-two acres and John E. Lyle and William Lewis donated forty acres each should the Institute be located on the south side of the Rickreall. A resolution was passed that each trustee be requested to act as a solicitor to obtain funds for the Institute. Soliciting meant going from one donation land claim to another. On July 12, 1855, the trustees laid out the twenty-four rod square for the Academy grounds and a street of eighty feet all around the lots one hundred by one hundred and fifty feet bordering. Lots around the square were to be offered for $100 each. Some were donated to merchants, taverns, blacksmiths, cabinet-makers and the like on the condition they commence building early next season. Homeowners were offered plots for $50. The funds raised from the sale of the lots were used for building the school and for educational purposes.
In 1857, LaCreole Academy had 57 students. WC Brown bought out Ellendale General Store for $2500 to be paid in full in one year, and moved it to Dallas. Business was so good; he was able to pay off his debt in six months. The first jail was built in the new Dallas site. The 1860 census listed the population as 449 with two physicians, a druggist, two schoolteachers, three clergymen, a baker, a hotel keeper, six or seven general stores, a saw and planing mill, a flour mill, a saddletree maker, and the woolen mill at Ellendale.