What's the difference between "near" and "nearby"?

This is a great question. It's also a hard one to answer in brief terms, but I’ll do my best!

Near and nearby are both synonyms for close. However, there are three clear and important differences in their meaning and use:

1) The first difference is that near is often used as a preposition, but nearbycan never be properly used as a preposition. Furthermore, when near is a preposition, it doesn’t simply mean close, it means close to, as shown in this example:

• I left the box near the door. [near means close to (the door)]
• I left the box nearby the door. [You may hear someone say this occasionally, but it is not considered correct.]

2) The second difference is that near can mean close in time (=soon), as well as close in distance, but nearby cannot, as shown below:

• Summer is drawing near. [near=close in time]
• May is nearby.  [nearby cannot mean close in time]

3) The third difference is that nearby can appear either before or after a noun that it describes, but near can normally appear only before the noun, and even then, only when referring to time.* Here are some examples:

• We slept at a nearby motel. [nearby + noun]
• We slept at a motel nearby. [noun + nearby]
• I hope to visit you in the near future. [near + noun, and near=close in time]
• I hope to visit you in your near home. [near cannot  be used before a noun to refer to distance]

*There is one exception to this near + noun restriction: It’s perfectly acceptable to use near + noun when referring to distance in a sentence that contrasts near with far, as in this example:

• The near side of the garage needs a paint job, but the far side looks okay

출처: http://www.learnersdictionary.com/qa/what-s-the-difference-between-near-and-nearby