Creating a full-fledged mobile number location finder with HTML, CSS, and JavaScript requires a complex backend infrastructure to query a database of mobile numbers and their associated locations. This is typically not something that can be achieved with just front-end technologies like HTML, CSS, and JavaScript. However, I can provide you with a simple example of how you might structure the front-end of a mobile number location finder:
```html
Mobile Number Location Finder
```
In this example, we have a basic HTML structure with an input field to enter a mobile number, a button to trigger the location search, and a paragraph element to display the result. However, please note that this is a simplified example and doesn't perform actual mobile number location lookup. Real mobile number location services require server-side programming and access to a database of phone number prefixes and their associated locations, which is beyond the scope of front-end development.