Census records are another resource that can help determine who lived at an address. While census records tend to be easier to search by name, it is possible to find addresses.
Lake County Public Library has digitized our collection of census indices, which can be downloaded here. We have indices of the United States Federal Census for Lake County for 1860, 1870, 1880, 1900, 1910, 1920 and 1930. We also have the Colorado State Census for 1885.
Using the same 318 W. 4th St. example, we already know some names that we can check for in the census.
1880 might be too early, as the first listing in the city directories was in 1882.
1885 - C. H. Livingston(e) was listed in city directories for 1882-1885, or Earnest E. Goodell who was listed in the city directory for 1886
1900 - Michael Schneider was listed in city directories for 1899-1902
1910 - we didn't find anyone listed
1920 - beyond the date of city directories
1930 - beyond the date of city directories
Let's look at 1910, since we didn't find any names while searching the city directory. First, you'll want to download and open the 1910 Census Index. In the front is the list of enumeration districts (an enumeration district is the area that a single enumerator could cover during the census period). This will help us determine where to look in the actual census pages.
First page of enumeration districts for 1910
From this list we see that enumeration district 69 covers West 4th Street for the 100-400 blocks. Now we can navigate to FamilySearch.org (or you can access the census records at Ancestry.com if you are a subscriber). If this is your first visit to FamilySearch.org, you will need to create a free account to access their records.
If you are not comfortable signing up for an account, send an email to firstname.lastname@example.org and include the address you are researching and any other relevant details.
After you create your account, you will want to go to the Search tab, and then to Records. From there you will see a world map on the right side, and find a collection with a search box. In the search box, type in United States Census, 1910. You will be greeted by a form to search for a deceased ancestor. At the bottom of the page is a link to 'browse through 2,162,782,' click that link, then click on the state you want (Colorado), then choose the county (Lake). Now you are presented with a list of wards and precincts. You may need to click through until you see the right enumeration district. In this example we are looking for ED 69.
Enumeration district 69 is listed under Leadville Ward 2:
Now we play detective until we find 318 West Fourth.
Luckily 318 West Fourth is listed on the first page for this enumeration district. West Fourth is written sideways in the first column, and the numbers in the second column are house numbers.
Now we know that Peter M. Peterson and his family were at 318 W. 4th at the time of the census in 1910.
This process can be repeated for the other census records. Again, if you need any assistance with the census records, please reach out to email@example.com.