dnd 5th – Does the Hunter Ranger counter-current combat feature require the new target to be within the reach of the first enemy?

Yes, the new target must be within range of the same attack

The description of the feature reads as follows:

Standing against the current. When a host creature misses you with a melee attack, you can use your reaction to force that creature repeat the same attack against another creature (other than herself) of your choice.

To launch an attack, you must do the following:

  1. Choose a target. Choose a target within range of your attack: a creature, an object, or a location.
  2. Determine the modifier. The DM determines whether the target is covered and whether you have an advantage or a disadvantage to the target. In addition, spells, special abilities, and other effects may apply penalties or bonuses to your attack roll.
  3. Solve the attack. You make the attack throw. On one blow, you deal damage, unless the attack is governed by contrary rules. Some attacks cause special effects in addition to or instead of damage.

The feature allows you to choose a target instead of the creature, but the requirement that it be within range of the creature's attack is not removed. Note that he must act from the same attack. That is, if you use a long vorpal sword during the previous attack, you can not change the attack to use a normal short sword. All "attacking" effects will apply automatically, for example if you have already launched Thunderous Smite and have always activated it. Paladin's Divine Punishment is not applied automatically, however.