For calculating population from village data it is necessary to know the number of houses per village and the number of inhabitants per house. Both these variables depend for their value upon numerous demographic and cultural factors and hence must be determined separately for nearly every tribe studied. Kroeber has paid special attention to the second variable, the number of inhabitants per house, and has concluded that the best value for the Yurok is 7.5 persons. Since all the contemporary accounts agree with this conclusion it may be accepted as established. With regard to the number of houses per village it must be admitted that this factor is subject to wide variation both in locality and time. The number of house pits observed many years after the village itself has disappeared is likely to be unreliable for many reasons, although it may be used as a first approximation in default of better data. A safer guide is the memory of reliable informants or actual house counts made by explorers or original settlers. These are the sources of the values given by Kroeber and Waterman. For the Yurok there are five chief compilations of villages, with and without house counts: 1. _Kroeber._ This author shows (1925, p. 18) a list of fifteen villages (four of them compound) which he says are "recent counts of houses or house pits recollected as inhabited." In addition he shows on his map (p. 9) a number of other towns, some of which he regards, and so designates, as being temporarily or intermittently inhabited and hence not to be included in any computation of permanent population. The house counts from his list are shown in table 2 (p. 92, herein) in the column headed "Kroeber, _modern memories_." 2. _Kroeber._ On page 18 as well as on page 16 is given a census for the fifteen villages mentioned above. This was made in 1852 by a "trader" named York who lived many years in the vicinity. The census has all the appearance of veracity and may be accepted as substantially accurate. It is shown in table 2 (p. 92, herein) in the column headed "Kroeber, _1852 census_". 3. _Waterman._ This author presents his findings, all from informants, in three ways. First are his textual descriptions, which are careful and circumstantial. Second are his maps of a few villages, on which the house locations are drawn with much detail. Third there is the summarizing list (1920, p. 206), in which most of the textual and other data are incorporated. With respect to house counts there are numerous discrepancies between text, list, and maps, some of which are difficult to reconcile. Since from the context it may be inferred that the list represents Waterman's final evaluation, it must be used as the basic source of information.