the distance that you can stretch out your arm to touch something
out of/beyond (somebody's) reach
Keep chemicals out of the reach of children.
within reach (of somebody)
Keep a glass of water within reach.
close to a place:
The beach is within easy reach of the hotel.
the limit of someone's power or ability to do something
beyond the reach of somebody
He lives in Paraguay, well beyond the reach of the British authorities.
the parts of a place that are furthest from the centre
the further/outer reaches of something
the further reaches of the jungle
the straight part of a river between two bends:
the upper reaches of the Nile
the high or low levels of an organization or system:
They lingered in the lower reaches of the Football League.