In a pan over medium heat, cook the bacon until browned and slightly crispy. Remove from the pan and add to the crockpot, leaving as much drippings as possible in the pan.
Add in the onion, celery, and butter. Cook until softened and onion is transparent, about 3-5 minutes.
Add in the flour and cook for 2 more minutes. Remove from heat and add to the crockpot.
Add the bacon and sautéed veggies, potatoes, add the clams with the juices, chicken stock, salt, and pepper.
Cook on high for 4 hours or low for 6-8 hours.
The last 45 minutes-hour of cooking, add in the half-and-half. If the soup is too thin once done, add a teaspoon of cornstarch at a time until your desired consistency.
Season with salt and pepper if needed. Serve with toppings of your choice.