36Yearbook of the AssociationVol. 18 TWO ISOCHRONIC MAPS OF SETTLEMENT IN OREGON Georgia Ellen Adams University of Oregon Following the examples of the Dodge1 and the Zelinsky2 isochronic studies of New England and Georgia respectively, I have attempted to analyze the settlement pattern of the state of Oregon.3 The importance of such a method for understanding the impact of settlement on the culture of this particular region is apparent when one realizes that even today Oregon has the major portion of population, political groupings and major industries in the Willamette valley, the area first settled by the pioneers. In addition to cultural values pertaining to settlement, I have attempted to determine the extent to which natural barriers and routes of transportation have affected settlement frontiers, as well as to determine the nature of the flow of settlement in Oregon from one place to another. There are few data in the many histories of Oregon that give specific historical settlement data for geographical locations in the state as a whole, though several have discussed settlement of the Willamette valley. In fact, there were many areas for which the data were so meager that these areas could not be adequately plotted on the accompanying maps. The first map includes some 600 dates which were gleaned from various state, county and local histories. (See Fig. I). These dates represent the first significant agricultural settlement for each area. As can be expected, there were few dates available for initial rural settlements. Land deeds were of little use in determining first settlements, as many of the pioneers failed to file a claim for from 5 to 20 years after settling on the land. The second map was plotted entirely from Payne's study of post offices in Oregon.4 (See Fig. 2). This list contained some 2000 cities and towns, giving both the date of opening and closing for each. However, many of these were representative of towns no longer in existence and of the total number only 902 could be plotted for this study. This map was done separately to show the differential in this type of information from those given as historical dates, although Zelinsky suggested a postal study as a possible means of determining settlement patterns. In order to interpret the accompanying maps, some of the historical and geographical features of the state will be included. There are four principal mountain ranges and several minor ones in the state. The Cascade mountains and the Coast Range both run north and south through the entire state, and have acted as primary natural barriers to the advancing frontiers. The Siskiyou mountains are located in the southern quarter of western Oregon and the Blue mountains in the north eastern quarter. All are 1956of Pacific Coast Geographers37 extremely rugged mountain chains, with the Coast Range being lower than are the other groups. The Cascade range divides Oregon into two distinct sections, western and eastern Oregon. Eastern Oregon consists largely of a high volcanic plateau, colder in winter, warmer in summer and considerably drier than the western part of the state. There are no great agricultural valleys in central Oregon, but in the far eastern section, the valleys of the Grande Ronde, Powder and Burnt rivers resemble those in western Oregon. Among the distinctive features of western Oregon are the numerous valleys formed by the several mountain chains, the principal ones being the Willamette, Rogue and Umpqua valleys. The Willamette is by far the most attractive in all respects, being approximately 150 miles long and fron 30-60 miles wide. It is the most thickly populated area in the state and is the best suited for varied agriculture. The Willamette River and its tributaries, along with that of the Columbia River, formed the major means of transportation for the early pioneers and at one time in the early pioneer history, a river steamer operated from the falls at Oregon City to the city of Eugene, a distance of almost 120 miles. Historically speaking, the region was first entered by an American in 1792, when Capt. Robert Gray discovered and ascended the Columbia River, thereby forming the basis for the subsequent claims to, and acquisition of, the...