As you're reading through the Old Testament, you'll find these odd references to "high places." Many of these places were pagan in nature and some of them even contained standing stones. These stones were not like the pillars that were created to commemorate an event (Joshua 4:2-3). Instead, standing stones were said to be a place that contained a deity. These stones were littered all throughout Israel and have pagan roots dating back to the time before Abraham.
This is probably the type of standing stones or rock pile that was assumed by Jacob as he's fleeing from Esau in Genesis 28:17-22. He creates a standing stone of his own as a place that he calls Bet 'El (Bethel). He gives this pile of rocks divine standing and establishes an official source of idolatry in that spot. Interestingly, it is Bethel that becomes a home of pagan worship for centuries following this account.
The practical question is what are the standing stones in our life? Are there things we have tucked in our heart or things we approach as objects of worship? It's easy to quickly dismiss the reality of standing stones in our lives, but it may be worth doing some evaluation. What do you do if you spot a standing stone in your life? Deuteronomy 7:5-6 gives us the command from the law of God of what we are to do with these when they are found.
But thus shall you deal with them: you shall break down their altars and dash in pieces their pillars and chop down their Asherim and burn their carved images with fire. For you are a people holy to the LORD your God. The LORD your God has chosen you to be a people for his treasured possession, out of all the peoples who are on the face of the earth. - Deuteronomy 7:5-6 (ESV)