The settlement would have spanned around half a kilometre in a field in the present day village of Philiphaugh, near Selkirk.
The remains were discovered during a Scottish Water project to lay new water mains between Howden and Yarrowford Water Treatment Works.
Archaeologists were on site looking out for potential items of interest while the work was going on.
Examination of crop marks on aerial photographs of the field initially suggested there may have been an Anglo-Saxon settlement on the site.
However, closer inspection of an area around a trench alongside the A708 suggests there may have been a medieval village sited there.
Charter evidence and other documents show there was an old Philiphaugh village in the area but the precise location was unknown.
Archaeologists are unsure whether they have uncovered old Philiphaugh village, but the remains do suggest a fairly large settlement rather than an individual farmhouse.
A number of stone buildings with stone floors were unearthed across the entire area, with cobbled areas in between.
Scottish Borders Council archaeologist Chris Bowles said: "We knew there had been something there, we just didn't know where it was. Now we have the village, and it is quite an extensive village.
"We have got a really extensive area of maybe half a kilometre where we have had buildings right along the road running to the salmon viewing centre."
Artefacts found on the site will now be closely examined and carbon dating used in a bid to give a more precise timeframe for when the settlement was inhabited.
Stewart Cooper, of Scottish Water, said: "The Borders is of course a particularly historic part of Scotland.
"While projects of this kind by Scottish Water are all about improving Scotland's water infrastructure they can often involve an element of digging and excavation - which can be fascinating when they help shed light on an area's past."
Meanwhile, a battered old suitcase which gives an insight into the life of a First World War nurse has been found at the back of a cupboard at a university.
Staff at the University of Abertay Dundee found the case, which belonged to a nurse called Margaret Maule, from Paisley, Renfrewshire, in the institution's psychology department.
It was filled with memorabilia from the war, and some of the documents show Ms Maule was sent to care for wounded German prisoners of war at Dartford War Hospital in Kent after finishing her training at Merryflatts Hospital (now the Southern General) in Glasgow in 1917.
Her diary was also inside the case, in which Ms Maule describes her initial misgivings about having to look after German soldiers, but later shows she was able to overcome those feelings to provide them with the care they needed.
She also treated wounded British soldiers at the Shakespeare Hospital in Maryhill, Glasgow, and later did her training to qualify as a Queen's Nurse in Greenock.
Among the memorabilia, which dates back almost 100 years to 1914, there are pictures of Ms Maule and some of her nursing colleagues in crisp, white uniforms.
Her brother is said to have been killed in action during the war.
The university said how the luggage case came to be there is a "complete mystery" as there are no records linking the woman to Abertay.
Staff have appealed for the public's help in shedding more light on Ms Maule's life.
Robin Ion, head of Abertay's nursing and counselling division, said: "The contents of this suitcase are absolutely fascinating, but we know very little about the person who owned it.
"There's no record of her ever having been to Abertay, so how it came to be in our possession is a complete mystery.
"All we know about her is what we've been able to piece together from the things we found in her suitcase.
"It contains documents dating back to 1914, including her diary and an article she wrote for a newspaper called The People's Journal.
"There's also an autograph book filled with detailed sketches drawn for her by her patients by way of thanks for the care she gave them, and a number of faded photographs of her and her fellow nurses dressed in their pristine white uniforms.
"When she graduated as a nurse at the age of 30 in 1917, after three years of training in Glasgow, she became part of Queen Alexandra's Imperial Military Nursing Service (QAIMNS) and signed up instantly to be sent overseas."
He added: "From the documents in the suitcase, we know that her brother had been killed in action, and that she was desperate to do her bit for the war effort.
"So it came as a shock when she learnt she was to be sent to Dartford to care for prisoners of war.
"However, the fact that she managed to carry out her duties in spite of her misgivings, and that she did so in such a way that her patients went to the trouble of crafting gifts for her to show their appreciation, indicates that she was one of the best.
"Nursing has always been about showing compassion - without prejudice - and nurse Maule showed an enormous depth of feeling to her patients under very difficult circumstances.
"If anyone knew nurse Maule, or has any information about where the suitcase might have come from, I'd be very keen to hear from them - she's a fantastic example of what nursing is all about and it would be wonderful if any of her relations alive today could tell us more about her."
Ms Maule's nursing record shows she was born in Paisley and lived in the town's McKerrell Street.
She trained at Merryflatts Hospital between 1914 to 1917, after attending the East Public School, Paisley.
The nurse retired in 1969 and a letter of appreciation for her service was sent to her at her home at 46 Dunchurch Road, Oldhall, Paisley, from the Ministry of Defence.
Anyone with information should contact the university at communications@abertay.ac.uk.
