You might choose to follow my suggested walk, which traces the lines of the original walls, including the surviving segments. Alternatively, you could just visit each of the gate sites individually. The route below is only a suggestion, which passes a few other unrelated caches on the way.
The complete wall walk tour is a distance of about 2 miles. It is mostly on the flat with a few steps at Bulwarks lane, and the stretch through Christchurch meadow is only accessible during daylight hours. However all the information you need to collect is on the flat and available at all times.
Information required:
Little Gate - This was first mentioned in 12A4.
South Gate - A blue plaque nearby records a birth in 1B93
East Gate - College buildings, marked by crests, were expanded in 1C52, 1C50 and 1C01.
Smith Gate - The bridge near here was built in 191D
Turl Gate - There are E cash machines at the former site of the Turl Gate
North Gate - St Michael's Saxon Tower was built in c10F0
West Gate - The Castle Tavern is number G4
Total of numbers for confirmation = 33
The cache is now a "camouflaged" container and is hidden just outside the limits of the old city. Stealth will be required. It should be easy to reach so PLEASE DO NOT MOVE ANYTHING ELSE. Using the information collected, the cache can be found at:
N51˚ 4(A+D-E) . (A+D+G) (E+F+G) (C-D)
W001˚ 1(C-B+A) . (D+G) E F
The starting coordinates are for the Little Gate, which consisted of two small arches, one for pedestrians and one for carts. It was formally known as Water Gate, being near several branches of the river Thames. Its presence explains why an otherwise straight road suddenly changes name from St Ebbes Street to Littlegate Street as one "leaves" the ancient city.
With your back to the plaque, head east along Brewer Street. Now part of Pembroke College, a tall section of the original wall runs along to your left, placing this street "outside" the city.
Brewer Street ends at the main highway of St Aldates that runs downhill towards the river. The South Gate (N51 44.985 W1 15.415), or Old Gate, spanned the road in line with the wall on Brewer Street until it was demolished in the 17th century. Like the other cardinal gates, it once had its own church, St Michael in the South Gate, which was removed in 1525 to make way for Christ Church College. There was no actual Saint Aldate - it is believed that the road is a corruption of the name of the gate itself: Aldgate (= Old Gate).
Cross over the main road and head right slightly until you can enter Christ Church meadows (open only during daylight hours). Follow the trail past the impressive frontage of Christ church and turn left at the sports field, following the path. The original wall would have followed a straight line from the segment on Brewer Street and South Gate before making a left turn north around St Frideswide's Priory, but all this again was demolished to make way for the college. However, the wall then turned east and our walk takes us along a lengthy and tall surviving stretch of the South Wall, with a bastion (fortified tower) jutting out at Merton College. The path you are on is known as Dead Man's Walk as it was the funerary route for the town's Jewish population, who were required to bury their dead outside the walls in their own cemetery in what is now the Botanic Garden. The city at this point was very well defended: in addition to the wall, the area was (and is!) very prone to flooding where the rivers Thames and Cherwell meet. The Thames ran in several different streams, including the Shirelake stream (marked by the line of a ditch and trees running across the meadow west-east) which formed the traditional boundary with Berkshire.
The bend in the wall shortly after the bastion is where the East Wall, which doesn't survive at this point, would meet the South Wall and head north towards the East Gate, in line with the modern buildings and hotel on Merton Street. However, our route turns slightly south east instead and we then follow the path round to the left and out through the meadow gate into Rose Lane with the Botanic gardens on the right.
Walk up to the High Street with Magdalen College opposite, which stood outside the town. Walk left and the Eastgate Hotel (with its High Table restaurant) marks the line of the wall. The East Gate (N51 45.141 W1 14.954), demolished in 1771 to widen the main road to London, spanned high street at this point.
A large segment of the East and North Walls are exceptionally well preserved in New College. Cross the High Street and head back east, then turn left to the north into Longwall Street, named after the wall. Unfortunately, the wall runs behind the buildings to the left and is not the wall to the east on the other side of the street. The road turns left into Holywell Street mirroring the north east corner of the wall and we can follow the line beside New College. At the gate of New College, take a peek through to see the long surviving segment of original wall. The wall at this point was, uniquely in England, a double wall but only the inner stretch survives. New College is usually open to the public but charges a fee (currently £4 per adult, free to Oxford residents on proof of address). I thoroughly recommend a look round if you have time to see the walls and five defensive bastions from the inside, which are still inspected annually by the mayor!
Walking down Holywell Street turn abruptly left into the cobbled alleyway of Bath Place, the site of the city's short-lived public baths, and pass left under the arch by the hotel to see the quaint Turf Tavern, with its 18th century front bar built on ancient foundations in the ditch outside the city wall. If you walk past the front of the pub you can see the original wall running down the side of the outhouse and it can be inspected from the rear garden when the pub is open. Follow the line of the wall right up St Helen's passage and out into the light under the Bridge of sighs and turn right for a view of several of Oxford's iconic buildings. The north wall continued its run east-west, interrupted as it crossed Catte Street by the tiny Smith Gate (N51 45.278 W1 15.252), which was little more than a "back door". However, it did have its own chapel, the chapel of Our Lady, a former tower of the wall which is the strangely octagonal building on the east side, now part of Hertford College.
Follow Broad Street to the west past the Bodleian Library and Wren's Sheldonian Theatre and old Ashmolean. The north wall here was flattened to make way for these buildings, meaning that Broad Street, with Trinity and Balliol colleges, was originaly outside the city.
Turn left at Turl Street, named after the Turl Gate (N51 45.243 W1 15.394), a twirling postern designed to keep cattle out of the city. Then head right into Ship Street, which ran on the inside along the wall with the modern buildings backing into some existing wall and towers, such as at the Tower House Hotel. Follow the road along to the junction with the Cornmarket and St Michael-at-the-Northgate church which, as the name suggests, was at the site of the North Gate (N51 45.223 W1 15.524), which spanned the street here and incorporated the city's prison, the Bocardo. The Saxon Tower of the church is probably the oldest existing structure in Oxford, predating the Norman castle.
Cross directly over to St Michael's Street. Again, the line of the wall, with a short surviving segment, ran along the back of the buildings to the right here. At the junction with New Inn Hall Street, the road previously made only a left hand turn as the wall ran along the north side. The street was only extended to George Street in 1872. Follow this extension right to George Street, peeking down the side of the Methodist church where a bastion of the wall was uncovered during its construction in 1870.
On George Street head left for a short distance, looking out the stretch of city wall (much reduced in height) to the left behind the History Faculty, before turning left up Bulwarks Lane immediately after the Four Candles. This tiny lane leads to George Street Mews - follow this curious alley alongside the wall to the left. On the other side of this wall is a short existing stretch which marks one of the ends of the town wall. The city had no west wall proper. Instead it merged with the extensive fortifications around Oxford castle, including both walls and moats (flooded ditches). Emerging onto New Road down Bulwarks Lane, we are inside the original castle perimeter and the Norman castle mound (1071) can be seen to the right.
Cross the road at the zebra crossing and head downhill on Castle Street. The modern pile of the Westgate centre is named after the West Gate (N51 45.051 W1 15.706), which straddled what is now Castle Street at about the junction with Paradise Street (named after extensive gardens next to the castle). This gate marked the resumption of the town wall from the castle complex. Castle Street winds to the left at the bottom end, following the line of the wall which has long since been built over in concrete at the back of the Westgate centre. A segment runs along the backs of the houses on the north side of Turn Again Lane before we return to the site of the Little Gate and complete our circuit.
I hope you enjoyed the tour!