Philips Point was a promontory on the north east bank of the Colorado River in Sonora Mexico that marked the mouth of the tidal estuary of the Colorado River in the later 19th century. "Philips Point may be regarded as the head of deep-water navigation in the Colorado River. At Philips Point spring tides rise 25 to 30 feet, and neap tides from 16 to 20 feet. At a short distance above Philips Point, the spring tide comes in with a bore or bank of water 4 feet high, extending in one huge breaker clear across the river, while the ebb is still running out. The influence of the tide in the Colorado River is felt for about 40 miles up the river, a few miles above Heintzelman's Point."