2005 California Government Code Sections 23070-23077 Article 1. Terms Defined

23070.  The terms and definitions contained in this article apply to
the boundary descriptions of the several counties, unless otherwise
declared.
23071.  In describing courses, "north," "south," "east," and "west,"
mean true courses, and refer to the true meridian.
23072.  "Northerly," "southerly," "easterly," and "westerly," mean
due north, due south, due east, and due west, unless controlled by
other words, or by lines, monuments, or natural objects.
23073.  "To," "on," "along," "with," or "by" a mountain or ridge,
mean summit point or summit line.
23074.  "To," "by," "along," "with," "in," "up," or "down" a creek,
river, slough, strait, or bay, mean the middle of the main channel
thereof.
23075.  "In," "to," or "from" the ocean shore mean a point three
miles seaward from the shore.  "Along," "with," "by," or "on" the
ocean shore, mean on a line parallel with and three miles seaward
from the shore.
23076.  The mouth of a creek, river, or slough which empties into
another creek, river, or slough, is the point where the middle of the
channels intersect.
23077.  The use of a county name specified in this division, without
further description, is a reference to the county of that name.