Leaflet and dplyr packages install

library(leaflet);library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

Your Simple Map

my_map = leaflet() %>% 
  addTiles()

Mark a specific address

my_map %>%
  addTiles() %>%
  addMarkers(lat=39.2980803, lng=-76.5898801,
             popup = "Jeff Leek's Office")

#Clustering Markers on the map

#coordinate sample data
df = data.frame(lat=runif(500, min=39.25, max=39.35),
                lng=runif(500, min=-76.65, max=-76.55))
df %>%
  leaflet() %>%
  addTiles() %>%
  addMarkers(clusterOptions = markerClusterOptions())

#Drawing circles for population area

md_cities = data.frame(name=c("Baltimore","Frederick","Rockville","Gaithersburg",
                              "Bowie","Hagerstown","Annapolis","College Park",
                              "Salisbury","Laurel"),
                       pop=c(619493,66169,62334,61045,55232,
                             39890,38880,30587,30484,25346),
                       lat=c(39.2920592,39.4143921,39.0840,39.1434,39.0068,39.6418,
                             38.9784,38.9897,38.3607,39.0993),
                       lng=c(-76.6077852,-77.4204875,-77.1528,-77.2014,-76.7791,
                             -77.7200,-76.4922,-76.9378,-75.5994,-76.8438))
md_cities %>%
  leaflet() %>%
  addTiles() %>%
  addCircles(weight=1,radius = sqrt(md_cities$pop)*30)
## Assuming "lng" and "lat" are longitude and latitude, respectively

#Add rectangles on the map.

leaflet() %>%
  addTiles() %>%
  addRectangles(lat1=37.3858,lng1=-122.0595,
                lat2=37.3890, lng2 = -122.0625)

#Using on the color to label records

df = data.frame(lat=runif(20, min=39.25, max=39.35),
                lng=runif(20, min=-76.65, max=-76.55),
                col=sample(c("red","blue","green"),20,replace=TRUE),
                stringsAsFactors = FALSE)
df %>%
  leaflet() %>%
  addTiles() %>%
  addCircleMarkers(color = df$col) %>%
  addLegend(labels = LETTERS[1:3], colors = c("blue","red", "green"))
## Assuming "lng" and "lat" are longitude and latitude, respectively