The problem with your question is that nobody really agrees on what the first rock and roll is, because different people attach different emphasis to different aspects of the music, and those different aspects came together in different ways, and different times. There isn't a right answer.

Firstly, it's useful to distinguish 'rock and roll' from 'rock'. Here, 'rock and roll' is the 1950s stuff mostly meant to be dance music, and 'rock' is the music of the 1960s that was influenced by 1950s rock and roll but took it in very different directions (e.g., rock like Jefferson Airplane's 'White Rabbit' in 1967 sounds very different to rock & roll like Chuck Berry's 'Rock & Roll Music' in 1957). This 'rock' perspective was enormously influential, because 'rock' effectively overtook jazz to become the new pop music norm in a way that 'rock & roll' did not. For someone coming from a 'rock' perspective (which is pretty much everybody in the West who grew up on Led Zeppelin and Bob Seger etc), they're going to focus way more on the aspects of 'rock & roll' that were carried on over into 'rock'. However, plenty of the original fans of rock & roll who never really liked a lot of what happened in the 1960s (e.g., famously Nik Cohn) might define it differently.

People from a 'rock' perspective might identify the 1952 'Rocket 88' by Jackie Brenston & His Delta Cats as the first rock'n'roll tune, partly because of the sound - it was a strongly blues-influenced band with prominent electric guitar which was doing their version of jive a la Louis Jordan. Brenston was the saxophonist in Ike Turner & His Kings Of Rhythm, and it was released under Brenston's name because he was the singer, but it was basically an Ike Turner production. And the lyrics are about a car, which is a very rock'n'roll thing to sing about (see Chuck Berry, The Beach Boys, Queen, etc) as far as the rockers were concerned. Ike Turner and band were from around Clarksdale, Mississippi, which is why they were the 'Delta Cats' (Clarksdale being on the same Mississippi Delta that gave birth to the 'Delta Blues'), but the song was recorded at Sam Phillips' Memphis Recording Service in Memphis, Tennessee (which later got rebranded Sun Studios). 'Rocket 88' (or perhaps some other songs) gets chosen, because it's the first song to have the sound that the later 'rock' fans wanted: it's upbeat, there's prominent electric guitar, there's louder drums than you might expect, lyrics about cars, without too many signifiers of big band jazz (there's plenty of music before 'Rocket 88' that basically doesn't sound dissimilar to 'Rocket 88' but which often sounds too jazzy and too clean to modern ears). Nobody knew until years later that 'Rocket 88' would be seen as the start of a new genre.

From another perspective, the thing that really distinguishes rock & roll from the rhythm & blues of the era is that it is made by young white people and/or for young white people. After all, the borders between rhythm & blues (the music Ike Turner would have understood himself to be making) and rock & roll were pretty porous; the disc jockey Alan Freed originally popularised the term 'rock & roll' to refer to a certain corner of rhythm & blues that he felt had an appeal to his white suburban youth audience. Perhaps the stuff played on Alan Freed's show was the first 'rock and roll', even if it doesn't quite sound right today.

But, putting Freed aside, from this perspective of the audience for the music, and depending on how big that audience had to be to really count, you could argue that Bill Haley's cover of 'Rocket 88' in 1951 might be the first rock & roll song, though it was only a regional hit. His first national hit, in 1953, was 'Crazy Man Crazy' by Bill Haley & The Comets. And of course, 'Rock Around The Clock', recorded in 1954, became an enormous worldwide hit in 1955. Perhaps one of those tunes - depending on where you draw the line - was the first rock & roll tune? It's not because it sounds that different to R&B, but because it was the first time a white band had some national American chart success doing, essentially, upbeat R&B that was clearly not aimed just at black people. In terms of the birthplace of this music, Bill Haley had started off making Western Swing music - basically, a countrified take on big band jazz - in Pennsylvania, and generally seems to have recorded at studios in New York.

Drawing that line there - it's the cover of 'Rocket 88' by a white guy that's the first rock'n'roll song, not the original, even though the original sounds more rock & roll - feels pretty weird. It's kinda racist. But then that's the point; genres only exist because of a group of people who want to hear a particular music. They don't exist outside of people's heads, because there's more to a genre than just the music itself. It's people who decide that this song is in the genre and that song is not, based on relatively arbitrary criteria. The prominent electric guitar in a song like 'Rocket 88', for example, was way more important to the 1960s rockers than it was to the 1950s rock & rollers, whose music was often piano based rather than guitar based - see Little Richard and Jerry Lee Lewis - and often had way more prominent saxophone than later rock music. Using it as a defining criteria of 'rock & roll' betrays a certain set of values. Which is to say that the other thing about genres is that they're not just sound - they're typically associated with social movements/scenes/subcultures with a shared aesthetic which goes into how people dress and act. After all, people making punk-sounding music but who (unironically) dress like ABBA might not quite be punk. And the demographic that rock & roll was aimed at, in the 1950s, was young and white - it was never going to be chart-toppingly popular by just appealing to African-American audiences.

So if we conceive of genres as audience-driven, the first rock & roll tune is the first one that the audience gravitates to, the one that turns a set of sounds into a genre. For that, we could finger Bill Haley's increasingly popular songs. But even still, 'Rock Around The Clock' was the first time the majority of the demographic for rock & roll heard the music. But that was one song, and not every popular song doing something new makes its way into being a genre. Perhaps you could argue that the song that caused the birth of rock and roll as a genre might be Kay Starr's 'Rock And Roll Waltz', which was perhaps the second rock & roll #1 after 'Rock Around The Clock' (you could also make a case for Pat Boone's cover of Fats Domino's 'Ain't That A Shame' which hit #1 on some but not all charts), but which more importantly has 'Rock and Roll' in the title specifically referring to a style of music - and lyrics like 'they were trying to waltz to a rock and roll song/ one, two and then rock, one, two and then roll'. To modern ears sounds a bit more like rocksploitation rather than true rock & roll, but there's certainly something indicative about a song with the name of the genre getting to #1 in the charts - and that indication is clearly that the genre has arrived. A month or two later, Elvis Presley would be at #1.

Speaking of which, Elvis's 'That's All Right' from 1954 has also been argued (in the pages of Rolling Stone) to be the first rock'n'roll record. As you'll notice, this is after the success of Bill Haley's 'Crazy Man Crazy', let alone 'Rocket 88'. But Elvis was white but also had cool, and this is not to be underestimated as a contributing factor to what makes rock & roll what it is - Bill Haley, for all his musical innovation, was not someone that young rock & rollers really aspired to being. But Elvis had cool. What cool is can certainly be debated, but to the white audience that Elvis appealed to, he was not only a very attractive young man but he had a certain 'soul'/'blackness' in his manner and his singing - while still clearly being white - which was missing from the well-enunciated and correct and proper sounding likes of Bill Haley, Pat Boone and Kay Starr. To be clear, later in his career, Elvis was no longer cool; in the eyes of the cool people later on, he was a big fat joke in Vegas that was widely parodied by the likes of Andy Kaufman. All the things that had once made him cool had become so widely imitated to be basically normal. But as a young man in the mid-1950s, Elvis was cool to the extent that everybody wanted to be Elvis or to be with Elvis. 'That's All Right' was a white guy singing a blues cover in 1954, and was recorded in the same building as Jackie Brenston's 'Rocket 88' (the Memphis Recording Service/Sun Studios), and so it had all the right demographics and the right sound...but because it's probably the case that the idea of cool was what the 1960s rockers took most from 1950s rock & roll rather than the sound. And that idea of cool came very squarely from Elvis rather than Bill Haley, Pat Boone or Kay Starr.

So the answer to your question really comes down to the answer to 'what is rock and roll?' And the answer to that is not clear, because the defining 'core' of rock and roll - the thing that would enable someone to say 'this is rock & roll, not R&B' - is contested, with different people thinking - rightly, from their perspectives - that it is different things. But I mean, Sun Studios in Memphis has as good a claim as any, thanks to 'Rocket 88' and 'That's All Right', as does the Pythian Temple Building in New York (where Bill Haley recorded 'Rock Around The Clock'). And why not add to the list the studios of the Cleveland radio station WJW (now the sports radio station WKNR, apparently), where Alan Freed's 1951-1954 broadcasts popularised the term 'rock & roll'?