Mo. Rev. Stat. § 46.159: Washington.

Beginning at a point in the middle of Grand River, opposite the mouth of Mineral Fork; thence in a northwesterly direction to the northeast corner of Washington County, as established by the surveyor of the counties of Franklin and Washington, being a point sixteen chains north of the quarter-section corner on the line between sections fourteen and fifteen, in township forty, north, range two, east; thence due west to the middle of Meramec River; thence due south to the middle of township thirty-five, range two, west; thence due east with subdivisional line in the middle of township thirty-five to range line between ranges three and four, east; thence due north by said range line to the middle of Big River, in township thirty-nine; thence by said river to the place of beginning.