Many services have been-and still are being-conceived on the internet.
For instance, we have Online Directories for Reverse Wireless Phone Searching.
Their services are especially useful for:

• checking out the identity of someone
• checking out the contacts of a husband or wife
• checking out unidentified callers

Wishful thinking - No National/Local directory for Cell Phones There is no such thing as a National Cell Phone Directory for public use, and so the thought of it is just wishful thinking.
Of course if it did exist, then it would be an awesome idea.
Unlike land phones, cell phones are considered its owner's personal property and therefore not listed on public databases like the white pages for anyone and everyone to access.
This is the very reason why a national phone directory does not exist! Land phones and mobile phones are not treated equally! We all have our own preferences and when it comes to phones, most people prefer mobile ones with which they can be in touch throughout.
Landlines are mostly preferred for official and commercial purposes.
A difference that stands out is the privacy attached to wireless phone numbers unlike the landlines which are usually publicly listed.
However, thanks to privately owned (not public domain property) online Reverse Cell Phone Directories, you have all the help you need in tracing any cell number.
Top Gains of Online Mobile Phone Directories

• The directories provide addresses, names, age, and more info on persons
• The directories allow users to carry out unlimited searches
• The directories are conveniently accessible - all you need is an internet connection
• The best directories have information on over 95% of the cellular phone users in the USA accounting for billions of individual records