Size and scope of my current world building project.

[Tsidqiyah he/him]

I need some perspective. i am working on a world and the primary continant  is a rough circle (think White Sand) with a circular lake at it's heart. the issue i have is my initial size projection a land mass 2400 (3870 km) miles across with the central lake being about 800 miles (1290 km) across. This would be roughly be the distance coast to coast along I-10 in the southern United State. The lake would be roughly the distance from Denver to the Mississippi River. 

Are these distances unrealistically large for a civilization to cross frequently? 

[EthanBassett he/him]

This depends largely on the time period your story takes place and what transportation technology exists. 

[Tsidqiyah he/him]

On the continent in question the tech level will be Elizabethan England (gunpowder, and wind/water mill powered automation but not yet to steam) while the outside world will be industrial revolution.

[Darkness Ascendant he/him]

Have you explained how the formation occured?

[Tsidqiyah he/him]

In world the land came to be due to the "Old Magics".

The truth is that it was essentially formed as part of a cosmic war. (Think of it like a crater but instead of a meteor hitting the planet we are talking a god crashing into the world.)

[The One Who Connects he/him]

Having a giant lake 800 miles across is a sign that the naval industry needs to be rather well developed to handle it. 

Consider the world itself, then look at what challenges a nation/people would have in daily life and build the tech level around that. I don't have good experience picking an era and working from there because of how much ends up changing.

[Spoolofwhool]

Well, if you're looking at a world with technology approximate to the Elizabethan Era, and whether the lake is really possible for quick crossings, consider what naval speeds were possible at the technological level as well navigation techniques and consider whether they would be applicable. 

Now, I did some research on the matter, and after a quick googling, I found that the it appears that a good speed for a ship at that time is about 7-9 knots. This would give 10.359 mph at best, aroundbouts. This would mean that it would take about 80 days to cross the lake straight through, assuming a good speed, keeping a straight course, and no weather delays, all of which I'm assuming to be possible. So, I wouldn't say it is too unrealistic. However, considering how much trouble people had initially with sailing to North America from Britain, the longer distance might prove to be interesting.

Now navigation would be a lot more tricky, and would probably require some imagination. At that time, navigation was performed primarily using a magnetic compass and reference positioning using the North Star and the horizon. As such, for this world, for either method to be possible, you need some sort of easily found celestial body which occupies a set position most of the time, and a magnetic north, or something of the like. Now, both are imprecise. However, if you established a North/South Star and an East/West Star, then navigation would be fairly precise. Otherwise, there would be a fair amount of imprecisions. Magnetic compass isn't very good because it just gives direction, not positioning. 

Anyhow, some food for thought when it comes to designing the navigation.

[Tsidqiyah he/him]

OH! sorry the lake is currently un-navigable. Due to the presence of giant beasts and a depth of only 3-5 feet it is almost a holy site that most of the populace avoids. that is why i am concerned about the size of the continent as a whole.

@The One Who Connects Thank for the thoughts on development i miss some of the finer details which can mess me up from time to time. I may be adjusting my civilizations soon.

@Spoolofwhool Thank you for the thoughts on general navigation I haven't started with those elements yet, but i will need to consider those for the outer world as most of the other land masses do have access to the wider oceans.

[Eagle of the Forest Path he/him]

@Spoolofwhool 800 miles of lake at around 10 miles per hour means 80 hours of sailing, not 80 days. But since that's not relevant any more...

Crossing the continent by land would be time-consuming, since your civilisation doesn't have steam-power yet, they don't have railroads. Transportation would have to rely on regular roads with wagons drawn by horses or whatever beast of burden you fancy having on your world. This would be further complicated by terrain such as mountains, forests or swampland. Under those conditions, 2400 miles would be a challenge, but not an insurmountable one. And again: time-consuming, so don't transport perishables.