Create Site Collections in Bulk from a CSV File using PowerShell in SharePoint 2016

PowerShell cmdlet New-SPSite is used to create new site collections in SharePoint. It takes URL and Owner mandatory parameters with other parameters. Here is an example:

Create SharePoint Site Collection Using PowerShell :

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

#Parameters to create new site collection
$SiteName = "Demo"
$SiteURL= "http://intranet.Crescent.com/sites/demo"
$SiteOwner = "Crescent\SPAdmin"
$SiteTemplate = "STS#0"
 
#create site collection with given parameters
New-SPSite -Url $URL -Name $SiteName -OwnerAlias $SiteOwner -Template $SiteTemplate

PowerShell to Create Multiple Site Collections in Bulk from a CSV File:
Lets add some error handling and wrap New-SPSite into a reusable PowerShell function, to create multiple site collections from a CSV file.

• Step 1: Create a CSV file in the below format. Populate the column values according to your requirements.
  
• Step 2: Use this PowerShell script to read from CSV and create site collections in bulk.
  

  Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
  
  #Function to Create new Site Collection
  Function Create-SPSite
  {
    param
      (
          [string]$Name  = $(throw "Please Provide the Site Name!"),
          [string]$URL = $(throw "Please Provide the Site URL!"),
          [string]$Owner = $(throw "Please Provide the Site Owner!"),
          [string]$Template = $(throw "Please Provide the Site Template!")
      )
  Try {
     #Set the Error Action
      $ErrorActionPreference = "Stop"
  
      #Check if the site collection exists already
      $SiteExists = Get-SPSite | where {$_.url -eq $URL}
      #Check if site exists in the recycle bin
      $SiteExistsInRecycleBin = Get-SPDeletedSite | where {$_.url -eq $URL}
   
      If($SiteExists -ne $null)
      {
          write-host "Site $($url) exists already!" -foregroundcolor red
      }
      elseIf($SiteExistsInRecycleBin -ne $null)
      {
          write-host "Site $($url) exists in the recycle bin!" -foregroundcolor red
      }
      else
      {
          #create site collection
          New-SPSite -Url $URL -Name $Name -OwnerAlias $Owner -Template $Template
          write-host "Site Collection $($url) Created Successfully!" -foregroundcolor Green
      }
  }
  catch {
      write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
      }
  Finally {
      #Reset the Error Action to Default
      $ErrorActionPreference = "Continue"
   } 
  }
  
  #Read from CSV and create site collection
  Import-Csv "C:\SitesToCreate.csv" | Foreach-Object { 
     Create-SPSite -Name $_.SiteName -URL $_.SiteURL -Owner $_.SiteOwner -Template $_.SiteTemplate  }
  

This script uses the combination of Import-Csv and SharePoint cmdlet to create multiple site collections in SharePoint. There are other parameters such as Content Database, Language, Site description, etc you can incorporate with this.