Starfleet had known of the Borg for nearly eighty years, and yet they had been classified as a None Threat to the Federation. Admiral Syries, the head of Star Fleet intelligence at the time had viewed what little information was present, mainly from the El' Aurian Refugees on what the Borg were and what they were capable of. However with mounting pressure from the Klingon and Romulan Empires at the time it had been his decision to file the matter so. 

Over what were the following years the information on the Borg was largely forgotten, archived away in the Classified section of Star Fleet Intelligence. In the year 2365, the Borg had been completely forgotten about as the Federation strode forward. What with the stable peace treaty with the Klingon Empire and the Romulan Empire remaining unnerving quiet Star Fleet's only major worry was the Cardassian War. 

The year 2365 was really the first inkling of what was to come though as after the first contact with the Romulan Empire in nearly 60 years took place. This initial first Contact was indeed spurred by the mysterious disappearance of colonies on each side of the Neutral Zone. 

Less than one year after, thanks to Q's mischeviousness The crew of the USS Enterprise were forced in to close combat with the Borg in system J-25, only just escaping with their lives by pleading with Q. 
Upon their return to Federation space Picard was debriefed by Admiral Hanson and at this point began the preparations for the coming Borg invasion. 

In a matter of weeks all none essential projects were put on hold and Starship production was doubled at all Fleetyards within the Federation. Design briefs for new weapon systems were laid out and advanced tactical preparation began shortly after with the fleet withdrawing closer to sector 001. 

However it seem the Federation had forgotten a major loophole in their plans. Nobody had considered that the Borg had Transwarp technology. 

In the year 2267 the Borg arrived in Federation space and summarily destroyed everything in their path. 
Starfleet, unprepared for the invasion scrambled all available starships to rendezvous at Wolf 359. Communications with the Klingon and Romulan Empires were opened immediately, however only a couple Klingon vessels were able to reach Wolf 359 in time for the battle. 

An Armada of 40 starships waited for the Borg at Wolf 359. Of the 42 ships only 2 survived the attack, the Starfleet vessel U.S.S. Endeavour NCC-71805 Nebula-class vessel and one Klingon vessel. 11,000 lives were lost that day and Star Fleet was left in shambles. 

Five hours later a task force of 24 Klingon warships and 8 Romulan Warbirds arrived at Wolf 359, the two bitter enemies putting aside their differences as the rescued the few survivors began. 
Two Warbirds and four Vor'Cha class cruiser's set course for sector 001, however due to the last minute intervention of the Enterprise they arrived in sector 001 too late. 

Within a day all of the survivors of Wolf 359 had been rescued. The combined fleet of 47 ships left no proverbial rock unturned in their efforts to find survivors. 

Now all that remains of the first feared Borg invasion is what has become known as the Ghost System, the Starship Graveyard ............ Wolf 359.

Ship name

Registry

Class

U.S.S. Liberator

NCC-67016

????-class

U.S.S. Yamaguchi

NCC- 26510

Ambassador-class

U.S.S. Agamemnon

NCC- 11638

Apollo-class

U.S.S. Gage

NCC- 11623

Apollo-class

U.S.S. Buran

NCC- 57580

Challenger-class

U.S.S. Ahwanee

NCC- 71620

Cheyenne-class

U.S.S. Melbourne

NCC- 62043

Excelsior-class

U.S.S. Roosevelt

NCC- 2573

Excelsior-class

U.S.S. Righteous

NCC- 47451

Excelsior-class

U.S.S. Firebrand

NCC- 68723

Freedom-class

U.S.S. Lalo

NCC- 43837

Mediterranean-class

U.S.S. Saratoga

NCC- 31911

Miranda-class

U.S.S. Bellerephon

NCC- 62048

Nebula-class

U.S.S. Endeavour

NCC- 71805

Nebula-class

U.S.S. Melbourne

NCC- 62043

Nebula-class

U.S.S. Kyushu

NCC- 65491

New Orleans-class

U.S.S. Princeton

NCC- 59804

Niagara-class

U.S.S. Bonestell

NCC- 31600

Oberth-class

U.S.S. Tolstoy

NCC- 62095

Rigel-class

U.S.S. Chekov

NCC- 53702

Springfield-class