In Rank Tracker, it's crucial to state the location with which Ahrefs will help you track your keywords. Different locations will reflect different keyword ranking positions.
Rankings in eg. Idaho, USA will be different from that in a different country, say Singapore.
Here's an example for the keyword "link building", where we're comparing the SERP of USA and Spain. The top ranking URLs are completely different:
Here are some questions you can ask yourself when choosing the locations:
Is your target audience from a specific country or multiple countries?
Is your business covering the whole of a country (say USA) or specific cities within or just 1 state (say Idaho)?
Where are your most prioritized markets (either by total addressable size or value)?
If you are unsure of the answers to the above questions, you could start with adding the country and the city or state you are physically present at the moment.
How to choose a more specific location than just a country
When adding keywords to rank tracker, first select the country, then secondly enter in the city, or zip code of the choice, and select the location closest to what you're looking for: