My cell is in my bino harness. Power pack in water tight and in top of pack lid. My cell is usually in airplane mode to save power and everything is minimized except my GoHunt app. That app has the area pre downloaded so its a go.
The newer phones are pretty water-proof. I carry mine in the Marsupial pouch (designed to carry a phone) that attaches to my pack strap. Holds it very snugly and is very handy when wanting to use Onx. I carry the battery pack, which is a slender lightweight Jackery w/integrated cord, in a qt. size ziplock in my pack.
I carry my cell phone in my pants. Like some others here I'm a big fan of the Wrangler activity pant from Walmart and it has a thigh pocket exactly the right size for my phone. It's a subtle effect but my phone weighs half a pound so it still reduces what I have weighing my pack down.
To save a little weight I got a unit with integrated cables and half the time I use a 5,000 mAh unit rather than the 10,000 size most folks carry. 5,000 is plenty for me for day trips and overnights, so why carry a bigger pack than I need?