In the same vein, it's not inappropriate to mention this book...

...this lists about 110 road racing circuits in Australia, of which about 16 or so are still operating. It does include a couple of 'speedways' but only in the context that they were places where the road racers raced because there were no road racing circuits or similar...
It also has a serious error in the Woody Point circuit, so anyone who wants this clarified should see my article about that 'circuit' in
Motor Racing Australia... 'circuit' here is again used loosely, as the event was a 'high speed reliability trial' run in an effort to convince the authorities that racing on public roads was actually safe. It failed...
From a radius of about 25 miles around my old haunting grounds... no longer with us are:
Westmead Speedway, about a third of a mile as I recall, ran through the fifties and into the sixties, maybe even to the early seventies. Was compulsorily acquired as part of the site of the huge Westmead Hospital which now saves many lives on the site.
Warwick Farm... 2.25 miles of fabulously interesting and tricky road race circuit in and around the horse race track/s and in use from late 1960 to late 1973. Scene of many a great race, many a great drive, was responsible for the upscaling of all things in racing in Australia during the early sixties, had a 0.9 mile (I think) Club circuit entirely within the horse tracks which was frequently used for testing by top drivers of the era.
Amaroo Park... conceived originally as a motor sport park of immense dimension by Oscar Glaser, carved out of the sandstone country by his earthmoving gear, included a dirt short circuit, bitumen hillclimb, motocross area and finally (but never completed... sadly) a great 2.5 mile GP circuit. This also had a provision for extension to 3.0 miles, and this latter part, with a small section of the major circuit, was ultimately completed and hosted racing on its 1.3something miles of walled death from 1967 to 1998 or 1999. The property was leased to the Australian Racing Drivers Club after the first few meetings were conducted by the Amaroo Sporting Country Club and there was a provision that enabled the ARDC to purchase the property at 1967 price (and a mighty agreeable 1967 price too, methinks) if they chose within three years.
Unfortunately the ARDC did this, thus ensuring that all that would ever happen there would be in keeping with maintaining what existed rather than completing Oscar's grand plan. It is now acreage housing and even the road that could used the main straight in the subdivision has been very expensively carved further up the hill and fill used to obliterate most of what could be seen as the original form of the circuit. It appears that the developers didn't want any ghosts of the place to remain attractive to race enthusiasts, but they did retain the lake that adorned the infield of the lower end of the circuit, as that was where some club members had their ashes scattered.
Parramatta Park... road racing course, using park roads, originally used 1938 but the meeting was canned after practice by the police. Later it saw racing on two different layouts between 1952 and 1955. This is literally only a few hundred yards from Westmead Speedway, and between it and...
Parramatta Speedway... using an oval within Parramatta Park or the sporting grounds that are either part of it or adjoin it. Parramatta Park is of some national significance, by the way, as it was originally the grounds of the first permanent residence of the Governor of the colony of New South Wales. This speedway probably ran from the late forties but was gone by the sixties... I think... others might know better.
Mount Druitt... a wartime airstrip alongside the railway line between Mount Druitt and St Marys, this was used early in the post-WW2 period for sprints and races on the airstrip. I'm unclear as to how the section that took the circuit up onto the hill where the Whalan High School now stands came into being, but this road meandered up there and back and extended the circuit length from 1.5 miles to 2.4 miles. This form saw racing from 1952 to 1958, finally being severely compromised by the lessee of the property, Belf Jones, running a plough in a zig-zagging line around the entire circuit to prevent further use. The circuit was essentially doomed by the introduction of the 1957 Speedways Act, which would require enormous amounts of fencing to be erected, and though nobody wanted to weigh in and do this work, I gather that they expected Jones to do it for them. He was finally acquitted of the malicious damage charge that had been laid against him for the plowing job a couple of years later. By 1970 the encroachment of public housing onto the site was beginning to make it impossible to track its course in the upper reaches of the extension. Today netball and soccer fields adorn much of the airstrip section and much of the area is public park, with occasional showings of bitumen to inspire the hearts of those who go in search of times long gone.
Penrith Speedway... a cricket ground in the late 1800s, an airfield in the early 1900s, a golf course, a multi-use patch of ground right alongside Penrith railway station in the extreme west of Sydney's modern day sprawl. In the 1920s Penrith was a smallish town with a river that attracted many weekend picnickers, and in 1924 a one mile dirt speedway was completed and went into action. It had a number of entrepreneurs using it over the following 17 years and saw some great action. The final meeting in April 1941 was followed by complete takeover by the Defence Department and it remained in their possession until very recently. All the while, however, a part of the speedway alignment was used as a road between buildings that were constructed, and this is preserved today as a memorial to the racing that took place on the site.
Windsor Speedway... frankly, I know little about it. It was right near Windsor station (as Westmead was a short walk from Westmead station and Penrith ditto), about half a mile, I think, saw racing from the fifties to the seventies IIRC.
Brooklands... a famous name for an infamous attempt. A one mile high banked oval which was formed up alongside Werrington railway station (between St Marys and Penrith) was never used. It was built in the mid twenties and remnants of the embankment were still there in the sixties, possibly even today, but I've not yet been able to find a way to find them. It's an area now devoted to either higher education or housing for disadvantaged kids or something.
Maroubra Speedway... This one was finished, saw the usual string of entrepreneurs trying to make a go of it... built 1925, using lots of concrete to form its high banking, it was 'five sixths of a mile around the inside of the saucer' and saw racing on and off from 1925 to the mid thirties, maybe 1937. Bugattis, Sunbeams and Ballots were among the cars imported especially to race there.
Schofields... used one runway and a simple string of taxiways at the HMAS Nirimba Fleet Air Arm base near Quakers Hill in the west of Sydney. Actually, it was an air force base first of all, racing was first held there in July 1958 and it was only a little more than a year till racing ended. Although I'm not sure of that... I thought Frank Matich ran the Lotus 15 there, and I don't think that was here in 1959... Terry might have got his dates wrong here. 2.3 miles to the lap, the place was only ever available for one day meetings and everything from implantation of facilities to total cleanup had to be completed in that day.
Marsden Park... another airstrip circuit, just up and down the strip, first used June 1946 (one of the very first race meetings after WW2) it was used periodically by different clubs into the late fifties, probably succumbed to the Speedways Act.